Characterization of timing jitter spectra in freerunning mode-locked lasers with 340 dB dynamic range over 10 decades of Fourier frequency Kwangyun Jung and Jungwon Kim* School of Mechanical, Aerospace and Systems Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea *Corresponding author: [email protected] Received Month X, XXXX; revised Month X, XXXX; accepted Month X, XXXX; posted Month X, XXXX (Doc. ID XXXXX); published Month X, XXXX We demonstrate a method that enables accurate timing jitter spectral density characterization of free-running mode-locked laser oscillators over more than 10-decade of Fourier frequency from mHz to tens MHz range. The method is based on analyzing both the input voltage noise to the slave laser and the output voltage noise from the balanced optical crosscorrelator (BOC), when two mode-locked lasers are synchronized in repetition rate by the BOC. As a demonstration experiment, timing jitter spectrum of a free-running mode-locked Er-fiber laser with a dynamic range of >340 dB is measured over Fourier frequency ranging from 1 mHz to 38.5 MHz (Nyquist frequency). The demonstrated method can resolve different noise mechanisms that cause specific jitter characteristics in free-running mode-locked laser oscillators for a vast range of time scales from <100-ns to >1000-s. OCIS Codes: (320.7090) Ultrafast lasers; (270.2500) Fluctuations, relaxations, and noise; (320.7100) Ultrafast measurements; (120.3940) Metrology. Spectral purity of electronic and photonic oscillators is important for advancing various scientific and engineering applications such as high-precision synchronization [1], high-speed and high-resolution sampling and analog-to-digital converters [2], timing, time-keeping and navigation systems, clock distribution and communication networking equipment, signal measurement instrumentation, and radars and lidars, to name a few. For the optimization of oscillator performances, accurate characterization of phase noise and timing jitter of periodic signals generated from the oscillators is first required. Recently it has been identified that femtosecond modelocked lasers can serve as ultralow-noise photonic and electronic oscillators: mode-locked lasers can generate both optical pulse trains with extremely low timing jitter and, via proper optical-electronic (O-E) conversion process, microwave signals with extremely low phase noise. Recent measurements showed that free-running, passively mode-locked fiber lasers can generate both ~100-MHz repetition rate optical pulse trains and 10-GHz microwave signals with integrated timing jitter well below a femtosecond (when integrated from 10 kHz to >10 MHz Fourier frequency) [3-5]. Due to the intrinsically low level of timing jitter (e.g., lower than 10-4 fs2/Hz at 10 kHz Fourier frequency [3,4]) and the equivalent phase noise (e.g., <-140 dBc/Hz at 10 kHz Fourier frequency for 10-GHz carrier [5]), the accurate measurement of timing jitter spectral density in mode-locked laser oscillators has been a challenge. Traditionally, the timing jitter of optical pulse trains was measured in an indirect way by characterizing the phase noise of microwave signals converted from the optical pulse trains via O-E conversion (typically, using fast (>GHz) photodetectors) [6]. After a bandpass filtering of one harmonic frequency component, the microwave signal is mixed in quadrature with low-noise electronic tracking oscillator, which can be performed by several commercially available signal source analyzers (such as [7]). Although this photodetection-based method is a simple method that can utilize microwave components and commercial instruments, its measurement dynamic range and resolution are insufficient for accurate characterization of mode-locked lasers. First, the measurement dynamic range and resolution are often limit by the shot noise and thermal noise in the photodetectors, which results in a typical measurement noise floor of ~ -140 to -150 dBc/Hz. In addition, the excess phase noise by amplitude-to-phase (AM-to-PM) conversion in the photodetection and microwave amplification can add unwanted timing jitter/phase noise, which is not part of real laser noise. This excess noise can be problematic for the accurate characterization of jitter in the low Fourier frequency when the laser is locked to a stable reference source. As an alternative, the use of balanced optical crosscorrelation (BOC) has recently enabled tens of attoseconds resolution characterization of the high-frequency timing jitter spectral density in mode-locked lasers up to the full Nyquist frequency [3,4,8]. The BOC-based timing detector method requires a low-bandwidth phase-locked loop (PLL), which uses two almost identical mode-locked lasers and locks the repetition rates of two lasers using a piezoelectric transducer (PZT)-mounted mirror driven by the output signal from the BOC via a proportionalintegral (PI) servo controller. Due to the nonlinear optic arXiv:1412.0161v1 [astro-ph.IM] 29 Nov 2014 Background optimization for a new spherical gas detector for very light WIMP detection Ali Dastgheibi-Fardв€—a , I. Giomatarisb , G. Gerbierb , J. DerrГ©b , M. Grosb , P. Magnierb , D. Jourdeb , E .Bougamontb , X-F. Navickb , T. Papaevangeloub , J. Galanb , G. Tsiledakisb , F. Piquemalc , M. Zampaoloc , P. Loaizac , I. Savvidisd . Saclay and LSM teams of - New Experiments With Sphere - network a LSM, CarrГ© Sciences, 73500 Modane and CEA Saclay - IRFU/SEDI - 91191 Gif s Yvette Saclay - IRFU/SEDI - 91191 Gif s Yvette CarrГ© Sciences, 73500 Modane d Aristotle University of Thessaloniki, Greece b CEA c LSM, E-mail: [email protected] The Spherical gaseous detector (or Spherical Proportional Counter, SPC) is a novel type of particle detector, with a broad range of applications. Its main features include a very low energy threshold independent of the volume (due to its very low capacitance), a good energy resolution, robustness and a single detection readout channel, in its simplest version. Applications range from radon emanation gas monitoring, neutron flux and gamma counting and spectroscopy to dark matter searches, in particular low mass WIMPвЂ™s and coherent neutrino scattering measurement. Laboratories interested in these various applications share expertise within the NEWS (New Experiments With Sphere) network. SEDINE, a low background prototype installed at underground site of Laboratoire Souterrain de Modane is currently being operated and aims at measuring events at very low energy threshold, around 100 eV. We will present the energy calibration with 37 Ar, the surface background reduction, the measurement of detector background at sub-keV energies, and show anticipated sensitivities for light dark matter search. Technology and Instrumentation in Particle Physics 2014, 2-6 June, 2014 Amsterdam, the Netherlands в€— Speaker. c Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. http://pos.sissa.it/ Ali Dastgheibi-Fard Spherical Proportional Counter 1. Introduction There is an increasing interest for low-background, low-energy threshold detectors to identify the dark matter in our universe and to study low-energy neutrino physics. The question of dark matter has indeed become essential to particle physics [1]. The search for WIMP (Weakly Interacting Massive Particles) dark matter is under intense development and relies on the detection of low energy recoils (keV scale) produced by the elastic interaction of WIMPSвЂ™s with the nucleus of the detector. Increasing the sensitivity level requires detector scalable in target mass to 1 ton whilst maintaining the ability to reject backgrounds. The development of such detectors remains a daunting challenge for nowadays and future low-background experiments. As for the light WIMPвЂ™s (< 10 GeV), the nuclear recoil energy (в€ј< keV) becomes extremely small, leading to a signal below threshold for most conventional solid or liquid state detectors. The challenge is to achieve a very low energy threshold, typically around 100 eV or below. Some new experimental ideas have come to maturity. Among them is the innovative Spherical Proportional Counter (SPC), a gaseous detector, initially proposed by I. Giomataris [3], which will allow to explore a new region of dark matter particles of very low mass. Radioactive background studies about the effect of the shield and radioactive contributions from used materials are necessary to understand and optimize the detection parameters. The low energy calibration and the reduction of the internal contamination of the inner surface of the detector and its effect on the detector background will be described below. 2. Detector description The detector consists of a large copper sphere (from 0.6 m to 1.3 m in diameter) and a small ball or sensor (from 3 mm to 16 mm in diameter) located at the center of the vessel, Figure 1: Left, 60 cm spherical detector and its tube for its operation from outside of shielding; right principle of operation of spherical gas detector thus forming a proportional counter. The ball is maintained at the center of the sphere by a metallic rod and is set at high voltage. The electric field varies in 1/r2 and is highly inhomogeneous along the radius, allowing electrons to drift to the central sensor in low field regions constituting most of the volume, while they trigger an avalanche within few mm around the sensor. 2 Nuclear halo of a 177 MeV proton beam in water Bernard Gottschalkв€—, Ethan W. CascioвЂ , Juliane DaartzвЂЎ and Miles S. WagnerВ§ arXiv:1412.0045v1 [physics.med-ph] 28 Nov 2014 December 2, 2014 Abstract The dose distribution of a monoenergetic pencil beam in a water tank may conveniently be divided into a core, a halo and an aura. The core consists of primary protons which suffer multiple Coulomb scattering (MCS) and slow down by multiple collisions with atomic electrons (Bethe-Bloch theory). Their number slowly decreases because of nuclear interactions, which feed the halo and aura. The halo consists of charged secondaries, many of them protons, from elastic interactions with H, elastic and inelastic interactions with O, and nonelastic interactions with O. By kinematic analysis we show that the radius of the halo is roughly one third of the beam range. The aura, extending many meters, consists of neutral secondaries (neutrons and Оі-rays) and the charged particles they set in motion. We have measured the core/halo at 177 MeV using a test beam offset in a water tank. The beam monitor was a plane parallel ionization chamber (IC) used as a proton counter and the field IC a dose calibrated Exradin T1. Thus our dose measurements are absolute. We took depth-dose scans at ten displacements from the beam axis ranging from 0 to 10 cm, adjusting the beam current and the sensitivity of the Keithley electrometer as required. The dose spans five orders of magnitude, and the transition from halo to aura is obvious. These data furnish an incisive test of Monte Carlo nuclear models. We present model-dependent (MD) and model-independent (MI) fits to these data. The MD fit separates the dose into core (electromagnetic), elastic nuclear, nonelastic nuclear, and aura components, and reveals roughly how much each process contributes. It has 25 parameters, and the goodness of fit (rms (measurement/fit) - 1) is 15%. The MI fit uses cubic spline fits in depth and radius. The goodness of fit is 9%, and this fit is more portable and conceptually simpler. We discuss the prevalent parameterization of the core/halo, originated by Pedroni et al. [1]. Several authors have improved on the Gaussian transverse distribution of the halo dose, but all retain (in varied notations) PedroniвЂ™s T (w), the radial integral of the depth-dose, multiplying both core and halo and motivating measurements with large вЂ�Bragg peak chambersвЂ™ (BPCs). We argue that this use of T (w), a mass stopping power which by its definition includes energy deposited by nuclear secondaries, is incorrect. The electromagnetic (Bethe-Bloch) mass stopping power should be used instead. In consequence, BPC measurements and the associated corrections are, in our opinion, irrelevant. Furthermore, using T (w) leads to spurious excess dose on the axis of the core around midrange, which may be significant in fields involving relatively few pencil beams. Reference [2] is a long version of the present paper. в€— Harvard University Laboratory for Particle Physics and Cosmology, 18 Hammond St., Cambridge, MA 02138, USA (corresponding author, bgottsch @ fas.harvard.edu) вЂ Francis H. Burr Proton Therapy Center, Mass. General Hospital, 30 Fruit Street, Boston, MA, USA 02114 вЂЎ Francis H. Burr Proton Therapy Center В§ Mevion Medical Systems Inc., 300 Foster St. Littleton, MA 01460, USA 1 1 This work has been submitted to the IEEE Nuclear Science Symposium 2014 for publication in the conference record. Copyright may be transferred without notice, after which this version may no longer be available. arXiv:1412.0228v1 [physics.ins-det] 30 Nov 2014 Performance of a Large-Area GEM Detector Prototype for the Upgrade of the CMS Muon Endcap System D. Abbaneo15 , M. Abbas15 , M. Abbrescia2 , A.A. Abdelalim8 , M. Abi Akl13 , W. Ahmed8 , W. Ahmed17 , P. Altieri2 , R. Aly8 , C. Asawatangtrakuldee3 , A. Ashfaq17 , P. Aspell15 , Y. Assran7 , I. Awan17 , S. Bally15 , Y. Ban3 , S. Banerjee19 , P. Barria5 , L. Benussi14 , V. Bhopatkar22в€— , Member, IEEE, S. Bianco14 , J. Bos15 , O. Bouhali13 , S. Braibant4 , S. Buontempo24 , C. Calabria2 , M. Caponero14 , C. Caputo2 , F. Cassese24 , A. Castaneda13 , S. Cauwenbergh16 , F.R. Cavallo4 , A. Celik9 , M. Choi31 , K. Choi31 , S. Choi29 , J. Christiansen15 , A. Cimmino16 , S. Colafranceschi15 , A. Colaleo2 , A. Conde Garcia15 , M.M. Dabrowski15 , G. De Lentdecker5 , R. De Oliveira15 , G. de Robertis2 , S. Dildick9,16 , B. Dorney15 , W. Elmetenawee8 , G. Fabrice27 , M. Ferrini14 , S. Ferry15 , P. Giacomelli4 , J. Gilmore9 , L. Guiducci4 , A. Gutierrez12 , R.M. Hadjiiska28 , A. Hassan8 , J. Hauser21 , K. Hoepfner1 , M. Hohlmann22в€— , Member, IEEE, H. Hoorani17 , Y.G. Jeng18 , T. Kamon9 , P.E. Karchin12 , H.S. Kim18 , S. Krutelyov9 , A. Kumar11 , J. Lee31 , T. Lenzi5 , L. Litov28 , F. Loddo2 , T. Maerschalk5 , G. Magazzu26 , M. Maggi2 , Y. Maghrbi13 , A. Magnani25 , N. Majumdar19 , P.K. Mal6 , K. Mandal6 , A. Marchioro15 , A. Marinov15 , J.A. Merlin15 , A.K. Mohanty23 , A. Mohapatra22 , S. Muhammad17 , S. Mukhopadhyay19 , M. Naimuddin11 , S. Nuzzo2 , E. Oliveri15 , L.M. Pant23 , P. Paolucci24 , I. Park31 , G. Passeggio24 , B. Pavlov28 , B. Philipps1 , M. Phipps22 , D. Piccolo14 , H. Postema15 , G. Pugliese2 , A. Puig Baranac15 , A. Radi7 , R. Radogna2 , G. Raffone14 , S. Ramkrishna11 , A. Ranieri2 , C. Riccardi25 , A. Rodrigues15 , L. Ropelewski15 , S. RoyChowdhury19 , M.S. Ryu18 , G. Ryu31 , A. Safonov9 , A. Sakharov10 , S. Salva16 , G. Saviano14 , A. Sharma15 , Senior Member, IEEE, S.K. Swain6 , J.P. Talvitie15,20 , C. Tamma2 , A. Tatarinov9 , N. Turini26 , T. Tuuva20 , J. Twigger22 , M. Tytgat16 , Member, IEEE, I. Vai25 , M. van Stenis15 , R. Venditi2 , E. Verhagen5 , P. Verwilligen2 , P. Vitulo25 , D. Wang3 , M. Wang3 , U. Yang30 , Y. Yang5 , R. Yonamine5 , N. Zaganidis16 , F. Zenoni5 , A. Zhang22 Manuscript received November 30, 2014. 1 RWTH Aachen University, III Physikalisches Institut A, Aachen, Germany 2 Politecnico di Bari, UniversitВґ a di Bari and INFN Sezione di Bari, Bari, Italy 3 Peking University, Beijing, China 4 University and INFN Bologna, Bologna, Italy 5 UniversitВґ e Libre de Bruxelles, Brussels, Belgium 6 National Institute of Science Education and Research, Bhubaneswar, India 7 Academy of Scientific Research and Technology, ENHEP, Cairo, Egypt 8 Helwan University & CTP, Cairo, Egypt 9 Texas A&M University, College Station, USA 10 Kyungpook National University, Daegu, Korea 11 University of Delhi, Delhi, India 12 Wayne State University, Detroit, USA 13 Texas A&M University at Qatar, Doha, Qatar 14 Laboratori Nazionali di Frascati - INFN, Frascati, Italy 15 CERN, Geneva, Switzerland 16 Ghent University, Dept. of Physics and Astronomy, Ghent, Belgium 17 National Center for Physics, Quaid-i-Azam University Campus, Islamabad, Pakistan 18 Chonbuk National University, Jeonju, Korea 19 Saha Institute of Nuclear Physics, Kolkata, India 20 Lappeenranta University of Technology, Lappeenranta, Finland 21 University of California, Los Angeles, USA 22 Florida Institute of Technology, Melbourne, USA 23 Bhabha Atomic Research Centre, Mumbai, India 24 INFN Napoli, Napoli, Italy 25 INFN Pavia and University of Pavia, Pavia, Italy 26 INFN Sezione di Pisa, Pisa, Italy 27 IRFU CEA-Saclay, Saclay, France AbstractвЂ”Gas Electron Multiplier (GEM) technology is being considered for the forward muon upgrade of the CMS experiment in Phase 2 of the CERN LHC. Its first implementation is planned for the GE1/1 system in the 1.5 <| О· |< 2.2 region of the muon endcap mainly to control muon level-1 trigger rates after the second long LHC shutdown. A GE1/1 triple-GEM detector is read out by 3,072 radial strips with 455 Вµrad pitch arranged in eight О·-sectors. We assembled a full-size GE1/1 prototype of 1m length at Florida Tech and tested it in 20-120 GeV hadron beams at Fermilab using Ar/CO2 70:30 and the RD51 scalable readout system. Four small GEM detectors with 2-D readout and an average measured azimuthal resolution of 36 Вµrad provided precise reference tracks. Construction of this largest GEM detector built to-date is described. Strip cluster parameters, detection efficiency, and spatial resolution are studied with position and high voltage scans. The plateau detection efficiency is [97.1 В± 0.2 (stat)]%. The azimuthal resolution is found to be [123.5 В± 1.6 (stat)] Вµrad when operating in the center of the efficiency plateau and using full pulse height information. The resolution can be slightly improved by в€ј 10 Вµrad when correcting for the bias due to discrete readout strips. The CMS upgrade design calls for readout electronics with binary hit output. When strip clusters are formed correspondingly without charge28 Sofia University, Sofia, Bulgaria University, Seoul, Korea 30 Seoul National University, Seoul, Korea 31 University of Seoul, Seoul, Korea в€— Corresponding authors: [email protected], [email protected] 29 Korea Preprint number: arXiv:1412.0194v1 [physics.ins-det] 30 Nov 2014 Measurement of the muon beam direction and muon flux for the T2K neutrino experiment K. Suzuki1,в€— , S. Aoki2 , A. Ariga3 , T. Ariga3 , F. Bay3,вЂ C. Bronner4 , A. Ereditato3 , M. Friend5 , M. Hartz4,8 , T. Hiraki1 , A.K. Ichikawa1 , T. Ishida5 , T. Ishii5 , F. Juget3,вЂЎ , T. Kikawa1,В§ , T. Kobayashi5 , H. Kubo1 , K. Matsuoka1,В¶ , T. Maruyama5 , A. Minamino1 , A. Murakami1, , T. Nakadaira5 , T. Nakaya1 , K. Nakayoshi5 , Y. Oyama5 , C. Pistillo3 , K. Sakashita5 , T. Sekiguchi5 , S.Y. Suzuki5 , S. Tada5 , Y. Yamada5 , K. Yamamoto6 , and M. Yokoyama7 1 Department of Physics, Kyoto University, Kyoto, Japan Kobe University, Kobe, Japan University of Bern, Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics (LHEP), Bern, Switzerland 4 Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, University of Tokyo, Kashiwa, Japan 5 High Energy Accerlator Research Organization (KEK), Tsukuba, Ibaraki, Japan 6 Department of Physics, Osaka City University, Osaka, Japan 7 Department of Physics, University of Tokyo, Tokyo, Japan 8 TRIUMF, Vancouver, British Columbia, Canada в€— E-mail: [email protected] 2 3 ............................................................................... The Tokai-to-Kamioka (T2K) neutrino experiment measures neutrino oscillations by using an almost pure muon neutrino beam produced at the J-PARC accelerator facility. The T2K muon monitor was installed to measure the direction and stability of the muon beam which is produced together with the muon neutrino beam. The systematic error in the muon beam direction measurement was estimated, using data and MC simulation, to be 0.28 mrad. During beam operation, the proton beam has been controlled using measurements from the muon monitor and the direction of the neutrino beam has been tuned to within 0.3 mrad with respect to the designed beam-axis. In order to understand the muon beam properties, measurement of the absolute muon yield at the muon monitor was conducted with an emulsion detector. The number of muon tracks was measured to be (4.06 В± 0.05) Г— 104 cmв€’2 normalized with 4 Г— 1011 protons on target with 250 kA horn operation. The result is in agreement with the prediction which is corrected based on hadron production data. вЂ Present address: Institute for Particle Physics, ETH Zurich, Zurich, Switzerland вЂЎ Present address: Institute of Radiation Physics, University Hospital and University of Lausanne, Lausanne, Switzerland В§ Present address: RCNP, Osaka University, Ibaraki, Osaka, Japan В¶ Present address: KMI, Nagoya University, Nagoya, Japan Present address: Toshiba Corporation, Kawasaki, Japan 1 typeset using PTPTEX.cls 1. Introduction The Tokai-to-Kamioka (T2K) experiment [1] is a long baseline neutrino oscillation experiment in Japan. The neutrino oscillation parameters are determined by measuring an accelerator-produced neutrino beam before oscillation with the near detector and near the oscillation maximum with the far detector. T2K began operation in January 2010. Since then, data corresponding to a total of 6.63 Г— 1020 protons on target (p.o.t.) had been collected up to May 2013. The T2K muon monitor [2] was installed to monitor the muon beam which is produced together with the neutrino beam from the decay of pions. As the muon monitor is the only detector to monitor the beam spill-by-spill, our strategy is to monitor the muon beam direction with a precision of 0.3 mrad for every beam spill, in order to better control the neutrino beam for the neutrino oscillation measurement. In this paper, we first provide an overview of the T2K experiment and the importance of a precise measurement of the muon beam direction in Sec. 2. Section 3 gives an overview of the components of the muon monitor. A method for reconstructing the profile of the muon beam with the muon monitor is described in Sec. 4. In this section we also show the systematic error in the beam direction measurement, which was estimated using both the actual beam data and MC simulation. The stability of the beam direction and its intensity during the T2K beam operation is discussed in Sec. 5. During the beam operation, measurements of the absolute muon yield were conducted using an emulsion detector. This result, and a comparison with the MC prediction, are shown in Secs. 6 and 7 respectively. 2. Overview of the T2K experiment T2K consists of: a neutrino beamline, producing an intense muon neutrino beam; a near detector complex, INGRID and ND280; and a far detector, Super-Kamiokande (Super-K). Using this setup, the experiment aims to measure the neutrino oscillation parameters. An overview of the T2K experiment is shown in Fig. 1. The Japan Proton Accelerator Research Complex (J-PARC) is a facility situated in Tokai, Japan. A proton beam is accelerated up to 30 GeV by the main ring synchrotron and is fast-extracted to the neutrino beamline. The neutrino beamline consists of two components as shown in Fig. 2: a primary and secondary beamline. In the primary beamline, the proton beam is transported to a graphite target every 2 to 3 seconds. The beam has a time structure of eight narrow bunches, 58 ns long with 581 ns intervals, in a single spill. The beam forms a two dimensional Gaussian distribution of в€ј4 mm 1Пѓ width corresponding to в€ј7 mm radius at the target. The target and other equipment used to produce the neutrino beam is situated in the secondary beam line, whose details are given in Sec. 2.1. The neutrino beam produced here is detected at ND280 and Super-K, and the oscillation parameters are then measured. 2.1. Creation of the neutrino beam at the secondary beamline Figure 3 provides an overview of the secondary beamline. All of the components in the beamline are contained in a single volume of в€ј 1500 m3 filled with helium gas, which is enclosed by a helium vessel. The proton beam, transported to the target via the primary beamline, first enters a baffle which works as a collimator. After passing through the baffle, 2 arXiv:1412.0088v1 [physics.ins-det] 29 Nov 2014 Assembly and Bench Testing of a Spiral Fiber Tracker for the J-PARC TREK/E36 Experiment Makoto Tabata1,в€— , SВґebastien Bianchin2 , Michael D. Hasinoff3 , Robert S. Henderson2 , Keito Horie4 , Youichi Igarashi5 , Jun Imazato5 , Hiroshi Ito1 , Alexander Ivashkin6 , Hideyuki Kawai1 , Yury Kudenko6 , Oleg Mineev6 , Suguru Shimizu4 , Akihisa Toyoda5 , and Hirohito Yamazaki7 1 Department of Physics, Chiba University, Chiba, Japan CanadaвЂ™s National Laboratory for Particle and Nuclear Physics (TRIUMF), Vancouver, Canada 3 Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada 4 Department of Physics, Osaka University, Toyonaka, Japan 5 Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK), Tsukuba, Japan 6 Institute for Nuclear Research (INR) of the Russian Academy of Sciences (RAS), Moscow, Russia 7 Research Center for Electron Photon Science, Tohoku University, Sendai, Japan 2 E-mail: [email protected] This study presents the recent progress made in developing a spiral fiber tracker (SFT) for use in the experiment TREK/E36 planned at the Japan Proton Accelerator Research Complex. This kaon decay experiment uses a stopped positive kaon beam to search for physics beyond the Standard Model through precision measurements of lepton universality and through searches for a heavy sterile neutrino and a dark photon. Detecting and tracking positrons and positive muons from kaon decays are of importance in achieving high-precision measurements; therefore, we designed and are developing the new tracking detector using a scintillating fiber. The SFT was completely assembled, and in a bench test, no dead channel was determined. KEYWORDS: tracker, scintillating fiber, kaon decay, lepton universality, J-PARC TREK/E36 1. Introduction We are currently developing a charged particle tracking detector, known as the spiral fiber tracker (SFT) [1], for use in the E36 experiment [2вЂ“4] scheduled at the K1.1BR beam line in the Hadron Experimental Facility of the Japan Proton Accelerator Research Complex (J-PARC). This positive kaon decay experiment will search for physics beyond the Standard Model by testing lepton flavor universality and searching for a heavy sterile neutrino and a dark photon [5вЂ“8]. To search for a violation of lepton universality, we focus, in particular, on precisely measuring the ratio of the kaon decay widths RK = О“(K + в†’ e+ ОЅ)/О“(K + в†’ Вµ+ ОЅ) using a stopped kaon beam. For this experiment, we are building a new TREK/E36 detector system (Fig. 1) by upgrading the experiment E246 apparatus [9, 10], which was based on a twelve-sector superconducting toroidal spectrometer that was previously used at the High Energy Accelerator Research Organization (KEK), Tsukuba, Japan. Conducting high-precision measurements depends on efficiently identifying and tracking charged particles (i.e., positrons and positive muons) from kaon decays. Particle identification is performed by measuring the time-of-flight (TOF) between the TOF1 and TOF2 scintillation counters, threshold aerogel Cherenkov (AC) counters with a refractive index of 1.08, and lead (Pb) glass Cherenkov (PGC) counters for robust analysis. As shown in Fig. 1(b), the TOF1 and AC counters surround the kaon stopping active target made of plastic scintillating fibers [11], and the TOF2 Prepared for submission to JHEP arXiv:1412.0593v1 [hep-ph] 1 Dec 2014 Optimised sensitivity to leptonic CP violation from spectral information: the LBNO case at 2300 km baseline S.K. Agarwalla,o L. Agostino,a M. Aittola,u A. Alekou,b B. Andrieu,x F. Antoniou,b R. Asfandiyarov,aa D. Autiero,y O. BВґ esida,k A. Balik,r P. Ballett,n I. Bandac,k D. Banerjee,g W. Bartmann,b F. Bay,g B. Biskup,b A.M. Blebea-Apostu,i A. Blondel,aa M. Bogomilov,c S. Bolognesi,k E. Borriello,ab I. Brancus,i A. Bravar,aa M. Buizza-Avanzini,a D. Caiulo,y M. Calin,z M. Calviani,b M. Campanelli,d C. Cantini,g G. Cata-Danil,i S. Chakraborty,ab N. Charitonidis,b L. Chaussard,y D. Chesneanu,i F. Chipesiu,i P. Crivelli,g J. Dawson,a I. De Bonis,r Y. Declais,y P. Del Amo Sanchez,r A. Delbart,k S. Di Luise,g D. Duchesneau,r J. Dumarchez,x I. Efthymiopoulos,b A. Eliseev,w S. Emery,k T. Enqvist,u K. Enqvist,e L. Epprecht,g A.N. Erykalov,w T. Esanu,z D. Franco,y M. Friend,h V. Galymov,y G. Gavrilov,w A. Gendotti,g C. Giganti,x S. Gilardoni,b B. Goddard,b C.M. Gomoiu,z,i Y.A. Gornushkin,q P. Gorodetzky,a A. Haesler,aa T. Hasegawa,h S. Horikawa,g K. Huitu,e A. Izmaylov,m A. Jipa,z K. Kainulainen,f Y. Karadzhov,aa M. Khabibullin,m A. Khotjantsev,m A.N. Kopylov,m A. Korzenev,aa S. Kosyanenko,w D. Kryn,a Y. Kudenko,m,t,s P. Kuusiniemi,u I. Lazanu,z C. Lazaridis,b J.-M. Levy,x K. Loo,f J. Maalampi,f R.M. Margineanu,i J. Marteau,y C. Martin-Mari,aa V. Matveev,m,q E. Mazzucato,k A. Mefodiev,m O. Mineev,m A. Mirizzi,ab B. Mitrica,i S. Murphy,g T. Nakadaira,h S. Narita,p D.A. Nesterenko,w K. Nguyen,g K. Nikolics,g E. Noah,aa Yu. Novikov,w A. Oprima,i J. Osborne,b T. Ovsyannikova,m Y. Papaphilippou,b S. Pascoli,n T. Patzak,a,l M. Pectu,i E. Pennacchio,y L. Periale,g H. Pessard,r B. Popov,x M. Ravonel,aa M. Rayner,aa F. Resnati,g O. Ristea,z A. Robert,x A. Rubbia,g K. Rummukainen,e A. Saftoiu,i K. Sakashita,h F. Sanchez-Galan,b J. Sarkamo,u N. Saviano,ab,n E. Scantamburlo,aa F. Sergiampietri,g,j D. Sgalaberna,g E. Shaposhnikova,b M. Slupecki,f D. Smargianaki,b D. Stanca,i R. Steerenberg,b A.R. Sterian,i P. Sterian,i S. Stoica,i C. Strabel,b J. Suhonen,f V. Suvorov,w G. Toma,i A. Tonazzo,a W.H. Trzaska,f R. Tsenov,c K. Tuominen,e M. Valram,i G. Vankova-Kirilova,c F. Vannucci,a G. Vasseur,k F. Velotti,b P. Velten,b V. Venturi,b T. Viant,g S. Vihonen,f H. Vincke,b A. Vorobyev,w A. Weber,v S. Wu,g N. Yershov,m L. Zambelli,h M. Zitok 1 Now at Instituut voor Kern- en Stralingsfysica, KU Leuven, 3001 Leuven, Belgium. Abstract: One of the main goals of the Long Baseline Neutrino Observatory (LBNO) is to study the L/E behaviour (spectral information) of the electron neutrino and antineutrino appearance probabilities, in order to determine the unknown CP-violation phase ОґCP and discover CP-violation in the leptonic sector. The result is based on the measurement of the appearance probabilities in a broad range of energies, covering the 1st and 2nd oscillation maxima, at a very long baseline of 2300 km. The sensitivity of the experiment can be maximised by optimising the energy spectra of the neutrino and anti-neutrino fluxes. Such an optimisation requires exploring an extended range of parameters describing in details the geometries and properties of the primary protons, hadron target and focusing elements in the neutrino beam line. In this paper we present a numerical solution that leads to an optimised energy spectra and study its impact on the sensitivity of LBNO to discover leptonic CP violation. In the optimised flux both 1st and 2nd oscillation maxima play an important role in the CP sensitivity. The studies also show that this configuration is less sensitive to systematic errors (e.g. on the total event rates) than an experiment which mainly relies on the neutrino-antineutrino asymmetry at the 1st maximum to determine the existence of CP-violation. EPJ Web of Conferences will be set by the publisher DOI: will be set by the publisher c Owned by the authors, published by EDP Sciences, 2014 Identified particle production and freeze-out properties in heavy-ion collisions at RHIC Beam Energy Scan program Sabita Das (for the STAR collaboration)1 , a arXiv:1412.0499v1 [nucl-ex] 1 Dec 2014 1 Institute of Physics, Bhubaneswar-751005, India Abstract. The first phase of Beam Energy Scan (BES) program at the Relativistic Heavy-Ion Collider (RHIC) was started in the year 2010 with the aim to study the several aspects of the quantum chromodynamics (QCD) в€љ phase diagram. The Solenoidal Tracker At RHIC (STAR) detector has taken data at sNN = 7.7, 11.5, 19.6, 27, and 39 GeV in Au+Au collisions in the years 2010 and 2011 as part of the BES programme. For these beam energies, we present the results on the particle yields, average transverse mass and particle ratios for identified particles in mid-rapidity (|y| < 0.1). The measured particle ratios have been used to study the chemical freezeout dynamics within the framework of a statistical model. 1 Introduction finite-temperature QCD calculations on the lattice it is theoretically established that the transition from QGP To understand the properties of matter under extreme to a hadron gas happens at high temperature and ВµB conditions of high temperature or density, heavy-ion close to zero and is a cross-over [6]. Several QCD-based collision experiments are conducted at RHIC in BNL and calculations [7] suggest existence of first-order phase the LHC in CERN. These are the conditions, in which transition at a lower T and large ВµB . Therefore, there the deconfined phase of QCD matter, the Quark-Gluon should be an end point for the first-oder phase transition Plasma (QGP), is created. It is conjectured that the formed in the QCD phase diagram, known as the critical point. hot and dense partonic matter rapidly expands and cools Several QCD based models and also calculations on down. During the evolution it undergoes a transition back lattice predict the existence of the critical point at high to the hadronic matter [1, 2]. Both RHIC and LHC have ВµB [8] and its exact location depends on the different confirmed the formation of the QGP in central Au+Au and Pb+Pb collisions [3, 4]. In QCD, there are three conserved charges, baryon number B, electric charge Q and strangeness S . Thus the equilibrium thermodynamic state of QCD matter is completely determined by temperature T ch and the three chemical potentials ВµB , ВµQ , and ВµS corresponding to B, Q and S respectively. The QCD phase diagram is plotted with the temperature (T ) as a function of baryon chemical potential (ВµB ) [5]. From a e-mail: [email protected] model assumptions [9, 11вЂ“13]. It is worth to mention that not all QCD-based models or lattice groups do predict the existence of critical point [14]. Theoretically, the phase diagram is explored through nonperturbative QCD calculations on lattice which indicates the energy scale can be explored experimentally. Now to explore various aspects of the QCD phase diagram[15] such as the search for the signals of phase boundary, and the search the location of the critical point has become Using MiniBooNE NCEL and CCQE cross section results to constrain 3+1 sterile neutrino models arXiv:1412.0461v1 [hep-ph] 1 Dec 2014 C Wilkinson, S Cartwright and L Thompson Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, United Kingdom E-mail: [email protected] Abstract. The MiniBooNE NCEL and CCQE cross-section measurements (neutrino running) are used to set limits in the в€†m2 в€’ sin2 П‘Вµs plane for a 3+1 sterile neutrino model with a mass splitting 0.1 в‰¤ в€†m2 в‰¤ 10.0 eV2 . GENIE is used, with a relativistic Fermi gas model, to relate EОЅ and the reconstructed quantities measured. The issue of uncertainty in the underlying crosssection model and its effect on the sterile neutrino limits is explored, and robust sterile neutrino limits are produced by fitting the sterile parameters and the axial-mass cross-section parameter simultaneously. 1. Introduction The large axial-mass (MA ) measured by MiniBooNE and other experiments has shown that simple RFG models are inadequate to describe experimental data from quasi-elastic neutrino scattering off nuclear targets. Although there has been a great deal of recent theoretical work developing more sophisticated cross-section models, a clear picture has yet to emerge (a recent summary can be found in [1]). Neutrino oscillation experiments use the measured event rate to infer detailed information about the flux, so a flawed cross-section model may bias results. There have been a number of studies investigating this bias in the context of three-neutrino mixing measurements (see for example [2, 3, 4]). Similarly, such a bias should be investigated for sterile neutrino results, which may be more susceptible as there is generally no way to measure the unoscillated flux. This work investigates the effect that uncertainty in an RFG cross-section model, with MA as the only free parameter, has on sterile limits produced by a simple analysis of MiniBooNE NCEL and CCQE cross-section data. It extends the work published in [5], which omitted the CCQE data because of the lack of bin correlations. Limits are set in the в€†m2 в€’ sin2 П‘Вµs plane for a 3+1 sterile neutrino model with a mass splitting 0.1 в‰¤ в€†m2 в‰¤ 10.0 eV2 using a number of different assumptions about the RFG model. We implicitly follow the assertion made in [6], that inflating MA provides a reasonable description of the data, though it is understood that this inflated MA value is effectively accounting for additional nuclear effects. We will refer to the inflated axial-mass as MAeff from now on. A worthwhile extension of this work would be to look at the effect that different cross-section models have on the sterile neutrino limits produced. There are two choices to be made regarding the simple cross-section model, and we demonstrate that their effects on the sterile limits are significant. The first is whether to sequentially fit MAeff then the sterile neutrino parameters, which is only statistically sound if MAeff and the sterile parameters are completely uncorrelated, or fit all parameters simultaneously. The former procedure was used in the MiniBooNE-SciBooNE sterile analyses [7, 8], which used the MiniBooNE measurement of MAeff as a constrained parameter in the fit, though it was noted that EPJ Web of Conferences will be set by the publisher DOI: will be set by the publisher c Owned by the authors, published by EDP Sciences, 2014 Chemical freeze-out parameters in Beam Energy Scan Program of STAR at arXiv:1412.0350v1 [nucl-ex] 1 Dec 2014 RHIC Sabita Das (for the STAR collaboration)1 , a 1 Institute of Physics, Bhubaneswar-751005, India Abstract. The STAR experiment at RHIC has completed its first phase of the Beam Energy Scan (BES-I) program to understand the phase structure of the quantum chromodynamics (QCD). The bulk properties of the в€љ system formed in Au+Au collisions at different center of mass energy sNN = 7.7, 11.5, 19.6, 27, and 39 GeV have been studied from the data collected in the year 2010 and 2011. The centrality and energy dependence of mid-rapidity (|y| < 0.1) particle yields, and ratios are presented here. The chemical freeze-out parameters are extracted using measured particle ratios within the framework of a statistical model. 1 Introduction onia [11] phase also appear in the QCD phase diagram in addition to the confined and de-confined phases [12]. Par- The heavy-ion collider experiments such as STAR at RHIC, ALICE at LHC were designed to investigate matter similar to that formed at the very early stages of the universe i.e. matter under extreme conditions of high temperature or density (or both) [1]. Similar to the matter in its primordial state, a deconfined state of quarks and gluons is created called Quark-Gluon Plasma (QGP) at both RHIC and LHC [2, 3]. The QCD as the theory of strong interactions predicts a transition at sufficiently high temperature T or baryon chemical potential ВµB from hadronic matter to QGP state. So, by varying the T and ВµB in laboratory we can study the phase transition associated with QCD matter [4вЂ“7]. The major part of the QCD phase diagram, which is generally known as the plot of T as a function of ВµB , consists of two phases [8]. These are the high temperature QGP phase, where the relevant degrees of freedom are quarks and gluons, and the hadronic phase at low temperature. Other interesting phases related to neutron stars [9], color superconductivity [10], and the quarkya e-mail: [email protected] ticle yields in high energy heavy-ion experiments at different collision energies can be used to obtain the T and ВµB that set up the chemical freeze-out line in the QCD phase diagram. It appears to be very close to the phase boundary between QGP and hadronic phase, especially at low ВµB . At high T and vanishing ВµB , finite temperature lattice QCD calculations has established the transition from QGP to a hadron gas is a cross-over [13]. The existence of a first-order phase transition has been predicted by several QCD-based calculations at lower T and ВµB [14]. The QCD critical point is a feature of the phase diagram, where the nature of the transition changes from a discontinuous (first-order) transition to an analytic crossover [15вЂ“19]. To explore the freeze-out diagram, i.e. search the possible phase boundary line and search for the possible QCD critical point, is a priority study at RHIC. For this, STAR has completed the first phase of the Beam Energy Scan (BES-I) program [20], collecting data from Au+Au collisions at center of mass energies of 7.7, 11.5, 14.5, 19.6, arXiv:1412.0269v1 [hep-ph] 30 Nov 2014 Quasi-eikonal and quasi-U-matrix unitarization schemes beyond the Black Disk Limit E. Martynov в€—вЂ December 2, 2014 Abstract Quasi-eikonal and quasi-U-matrix unitarization of the standard Regge-pole amplitude for О±(0) > 1 have been considered. We show that some violation of unitarity even at high energy exists in both models. We have found in quasi-eikonal model a bump-oscillation structure of ImH(s, b) at large values of impact parameter b but where ImH(s, b) is closed to the maximal value. We argue that it is possible to choose the parameter regulating deviation of generalized models from pure eikonal or U-matrix modes in order to restore unitarity. It was shown in the recent paper [1] that the impact-parameterв€љamplitude H(s, b) extracted from pp elastic scattering data of the TOTEM experiment at s = 7 TeV [2] exceeds the black disk (BDL) limit ImH(s, 0) = 1/2. We define H(s, b) as the following transformation of standard scattering amplitude (at high s) в€ћ 1 H(s, b) = 8ПЂs 0 1 Пѓt = ImA(s, 0), s dq qJ0 (qb)A(s, t = в€’q 2 ), в€љ dПѓ 1 = |A(s, t)|2 . dt 16ПЂs2 (1) s = 7 TeV are shown in Fig. 1 (the figure is taken The extracted data for ImH(s, b) at from the [1]). This result, provided that it will be confirmed at higher energies (8, 13, 14 TeV at LHC), leads to the important consequences for many phenomenological models constructed within a hypothesis that the BDL regime is realized in hadron elastic scattering at high energy. First of all it concerns with a widely explored eikonal model 2iH (E) (s, b) = e2ih(s,b) в€’ 1 (2) where usually and in accordance with Regge approach an input amplitudes a(s, t) and h(s, b) are assumed to have the following properties. вЂў Amplitude a(s, t) is presumably imaginary at least at small t. вЂў Amplitude h(s, b) в€ќ i(в€’is/s0 )Оµ where Оµ > 0 and s0 = 1 GeV at fixed impact parameter b and at s в†’ в€ћ. в€— вЂ Bogolyubov Institute for Theoretical Physics, Metrolologichna 14b, Kiev, UA-03680, Ukraine email: [email protected] 1 P REPARED FOR SUBMISSION TO JHEP YITP-SB-14-49 arXiv:1412.0018v1 [hep-ph] 28 Nov 2014 Illuminating Dark Photons with High-Energy Colliders David Curtin,a Rouven Essig,b Stefania Gori,c and Jessie Sheltond a Maryland Center for Fundamental Physics, University of Maryland, College Park, MD 20742, USA C.N. Yang Institute for Theoretical Physics, Stony Brook University, Stony Brook, NY 11794, USA c Perimeter Institute for Theoretical Physics, 31 Caroline St. N, Waterloo, Ontario, Canada d 1110 West Green Street Urbana, IL 61801, Dept of Physics, University of Illinois at Urbana-Champaign b E-mail: [email protected], [email protected], [email protected], [email protected] A BSTRACT: High-energy colliders offer a unique sensitivity to dark photons, the mediators of a broken dark U (1) gauge theory that kinetically mixes with the Standard Model (SM) hypercharge. Dark photons can be detected in the exotic decay of the 125 GeV Higgs boson, h в†’ ZZD в†’ 4 , and in Drell-Yan events, pp в†’ ZD в†’ . If the dark U (1) is broken by a hidden-sector Higgs mechanism, then mixing between the dark and SM Higgs bosons also allows the exotic decay h в†’ ZD ZD в†’ 4 . We show that the 14 TeV LHC and a 100 TeV proton-proton collider provide powerful probes of both exotic Higgs decay channels. In the case of kinetic mixing alone, direct Drell-Yan production offers the best sensitivity to ZD , and can probe 9 Г— 10в€’4 (4 Г— 10в€’4 ) at the HLLHC (100 TeV pp collider). The exotic Higgs decay h в†’ ZZD offers slightly weaker sensitivity, but both measurements are necessary to distinguish the kinetically mixed dark photon from other scenarios. If Higgs mixing is also present, then the decay h в†’ ZD ZD can allow sensitivity to the ZD for 10в€’9 в€’ 10в€’6 (10в€’10 в€’ 10в€’7 ) for the mass range 2mВµ < mZD < mh /2 by searching for displaced dark photon decays. We also compare the ZD sensitivity at pp colliders to the indirect, but model-independent, sensitivity of global fits to electroweak precision observables. We substantially update previous work in the literature by performing a global electroweak fit of the dark photon model. Electroweak precision measurements at LEP, Tevatron, and the LHC exclude as low as 3 Г— 10в€’2 . Sensitivity can be improved by up to a factor of в€ј 2 with HL-LHC data, and an additional factor of в€ј 4 with ILC/GigaZ data. A R X IV E P RINT: nnnn.nnnn arXiv:1412.0619v1 [hep-ex] 1 Dec 2014 Low-Mass Dielectron Production in pp, pвЂ“Pb and PbвЂ“Pb Collisions with ALICE Patrick Reichelt (for the ALICE Collaboration) Institut fВЁ ur Kernphysik, Goethe-UniversitВЁ at Frankfurt am Main, Germany E-mail: [email protected] Abstract. The ALICE Collaboration measures the production of low-mass dielectrons in pp, pвЂ“Pb and PbвЂ“Pb collisions at the LHC. The main detectors used in the analyses are the Inner Tracking System, Time Projection Chamber and Time-Of-Flight detector, all located around mid-rapidity. The production of virtual photons relative to the inclusive yield in pp collisions is determined by analyzing the dielectron excess with respect to the expected hadronic sources. The direct photon cross section is then calculated and found to be in agreement with NLO pQCD calculations. Results from the invariant mass analysis in pвЂ“Pb collisions show an overall agreement between data and hadronic cocktail. In PbвЂ“Pb collisions, uncorrected backgroundsubtracted yields have been extracted in two centrality classes. A feasibility study for LHC run 3 after the ALICE upgrade indicates the possibility for a future measurement of the early effective temperature. 1. Introduction The measurement of electron-positron pairs (dielectrons) in the low invariant mass region allows studying the vacuum and in-medium properties of light vector mesons. Additionally, lowmass dielectrons are produced by internal conversion of virtual direct photons. They are excellent probes to study all collision stages, since they pass through the created medium almost unaffected. To quantify modifications of the dielectron production in heavy-ion collisions, measurements in pp collisions serve as a reference, while the analysis of p-A collisions allows disentangling cold from hot nuclear matter effects. In ALICE [1] at the LHC, dielectron measurements are performed using the central barrel detectors around mid-rapidity. Electrons can be identified via their specific energy loss in the Inner Tracking System (ITS) and the Time Projection Chamber (TPC), combined with time-of-flight information from the TOF detector [2]. In this proceedings we present a virtual direct photon measurement in pp collisions and the invariant mass analyses in pвЂ“Pb and PbвЂ“Pb collisions. Prospects of a future measurement in PbвЂ“Pb after the ALICE upgrade for LHC run 3 are also discussed. в€љ 2. Virtual direct photon production in pp collisions at s = 7 TeV в€љ The analysis presented here is based on 3 В· 108 minimum bias pp collisions at s = 7 TeV, recorded in 2010. Fiducial cuts on transverse momentum (pT > 0.2 GeV/c) and pseudorapidity (|О·| < 0.8) are applied to electron candidates. A clean electron sample is achieved by cuts on the time-of-flight and on the dE/dx in the TPC. Dielectron spectra are created for unlike-sign and like-sign combinations of these particles. The unlike-sign distribution contains a superposition arXiv:1412.0570v1 [hep-ex] 1 Dec 2014 Measurement of the charge asymmetry in dileptonic decays of top quark pairs in pp collisions at в€љ s = 7 TeV using the ATLAS detector C Deterre1 on behalf of the ATLAS Collaboration 1 DESY, Notkestrasse 85, 22607 Hamburg, Germany E-mail: 1 [email protected] Abstract. A measurement of the topвЂ“antitop (ttВЇ) charge asymmetry is presented using 2011 LHC data collected by the ATLAS detector corresponding to an integrated luminosity of 4.6 fbв€’1 at a centre-of-mass energy of 7 TeV. The analysis is performed in the dilepton channel, and two different observables are studied: AC , based on the identified charged ВЇ leptons, and AtCt , based on the reconstructed ttВЇ final state. The asymmetries, measured to ttВЇ = 0.021 В± 0.025 (stat.) В± 0.017 (syst.), are be AC = 0.024 В± 0.015 (stat.) В± 0.009 (syst.) and AC in agreement with the Standard Model predictions. 1. Introduction This analysis [1] uses a data set corresponding to an integrated luminosity of 4.6 fbв€’1 of Large Hadron Collider (LHC) protonвЂ“proton (pp) collisions at a centre-of-mass energy of 7 TeV collected by the ATLAS [2] detector. It is performed in the dilepton channel of the ttВЇ decay. The measured observables are the lepton-based charge asymmetry AC and the ttВЇ charge asymmetry AtCtВЇ. AC is defined as an asymmetry between positively and negatively charged leptons: AC = N (в€†|О·| > 0) в€’ N (в€†|О·| < 0) , N (в€†|О·| > 0) + N (в€†|О·| < 0) (1) where в€†|О·| = |О· + | в€’ |О· в€’ |, О· + (О· в€’ ) is the pseudorapidity1 of the positively (negatively) charged lepton and N is the number of events with positive or negative в€†|О·|. The AtCtВЇ corresponds to the asymmetry in top and antitop quark rapidities2 : ВЇ AtCt = N (в€†|y| > 0) в€’ N (в€†|y| < 0) , N (в€†|y| > 0) + N (в€†|y| < 0) (2) where в€†|y| = |yt | в€’ |ytВЇ|, yt (ytВЇ) is the rapidity of the top (antitop) quark, and N is the number of events with positive or negative в€†|y|. In Standard Model (SM) ttВЇ production, the asymmetry is absent at leading-order (LO) Quantum Chromodynamics (QCD) and is introduced by the next-to-leading-order (NLO) QCD 1 The pseudorapidity is defined in terms of the polar angle Оё as О· = в€’ ln tan(Оё/2). E+pz The rapidity is defined as: y = 12 ln Eв€’p where E is the energy of the particle and pz is the component of the z momentum along the LHC beam axis. 2 Single Top Quark Measurements at the Tevatron arXiv:1412.0500v1 [hep-ex] 1 Dec 2014 Manfredi Ronzani (on behalf of the CDF and D0 collaborations) Albert-Ludwigs-UniversitВЁ at Freiburg, Physikalisches Institut, Hermann-Herder-StraГџe 3a, D-79104 Freiburg, Germany E-mail: [email protected] Abstract. This paper reports the most recent measurements of single top quark production performed by CDF and D0 collaborations in proton-antiproton collisions at Tevatron. Events are selected in the lepton+jets final state by CDF and D0 and in the missing transverse energy plus jets final state by CDF. The small single top signal in s-channel, t-channel and inclusive s+t channel is separated from the large background by using different multivariate techniques. We also present the most recent results on extraction of the CKM matrix element |Vtb | from the single top quark cross section. 1. Introduction The Fermilab Tevatron Collider was in operation until September 2011 and in the RunII it в€љ provided 12 fbв€’1 of pВЇ p collisions at center of mass energy of s = 1.96 TeV. The D0 and CDF detectors recorded 10 fbв€’1 of proton-antiproton data per experiment. The top quark was observed at the Tevatron by CDF [1] and D0 [2] in 1995 in ttВЇ pairs produced via strong interaction that is the top quark primary production mode. The Standard Model (SM) predicts top quark to be produced also singly via electroweak interaction (single top) with three different production processes (Fig.1): t-channel with the exchange of a virtual W boson [3], s-channel with the W boson decaying into a top and an antibottom quarks [4] and the Wt-channel with the associate production of a W boson and a top quark [5]. While the first two production modes have a small but measurable cross section at Tevatron (around 2 pb and 1 pb, respectively) the Wt production mode has a cross section of 0.25 pb, that makes its contribution to the signal rate negligible. Single top quark was first observed in 2009 by CDF [6] and D0 [7] experiments with an inclusive search in s+t combined channels. The measurement in each single channel is done differently at the Tevatron and LHC, taking in account the differences in the production cross sections [3, 4, 5]. The t-channel is the dominant process at both the Tevatron and LHC and it has been observed by D0 in 2011 [8] and then established by ATLAS [9] and CMS [10]. The Wt-channel is visible only at the LHC and it has been observed by CMS collaboration at 8 TeV [11]. The s-channel has a relatively small cross section at both Tevatron and LHC but at LHC the signal to background ratio is smaller, that gives an advantage for the observation to the Tevatron experiments. The single top quark cross section measurement is proportional to |Vtb |2 , where |Vtb | is element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix. A direct measurement of |Vtb | is therefore possible, that is also a test of the unitarity of the CKM matrix and it can constrain extensions of the SM, for example with fourth quark generation [12]. December 2, 2014 5:25 WSPC/INSTRUCTION FILE phipsi venelin-proceedings- arXiv:1412.0243v1 [hep-ex] 30 Nov 2014 International Journal of Modern Physics: Conference Series c COPYRIGHT CERN on behalf of the NA62 Collaboration under CC BY-NC 3.0 MEASUREMENT OF THE RATIO OF THE CHARGED KAON LEPTONIC DECAYS AT NA62 Venelin Kozhuharovв€— Laboratori Nazionali di Frascati - INFN, 40 E. Fermi, Frascati (Rome), Italy Faculty of Physics, University of Sofia вЂњSt. Kl. OhridskiвЂќ, 5 J. Bourchier Blvd., Sofia, Bulgaria [email protected] Received 30 11 2013 Revised 30 11 2013 The ratio of the leptonic charged kaon decays RK = О“(K В± в†’ eВ± ОЅ)/О“(K В± в†’ ВµВ± ОЅ) is sensitive to the structure of the week interactions and can be precisely calculated within the Standard Model. Presence of New Physics can introduce a shift on its value of the order of a percent. The NA62 experiment at CERN SPS used data from a dedicated run in 2007 to perform a measurement of this ratio and probe the lepton universality. The data analysis technique and the final results are presented. Keywords: kaon decays, lepton universality, rare decays PACS numbers:13.20.Eb, 11.30.Hv 1. Introduction Within the Standard Model the dilepton charged pseudoscalar meson decays proceed as tree level processes through a W exchange. However, the helicity conservation leads to a strong suppression of the electron mode. The Standard Model (SM) expression for the ratio RK = О“(Ke2)/О“(KВµ2) is a function of the masses of the в€— Speaker, for the NA62 Collaboration: F. Ambrosino, A. Antonelli, G. Anzivino, R. Arcidiacono, W. Baldini, S. Balev, S. Bifani, C. Biino, A. Bizzeti, B. Bloch-Devaux, V. Bolotov, F. Bucci, A. Ceccucci, P. Cenci, C. Cerri, G. Collazuol, F. Costantini, A. Cotta Ramusino, D. Coward, G. DвЂ™Agostini, P. Dalpiaz, H. Danielsson, G. Dellacasa, D. Di Filippo, L. DiLella, N. Doble, V. Duk, J. Engelfried, K. Eppard, V. Falaleev, R. Fantechi, M. Fiorini, P.L. Frabetti, A. Fucci, S. Gallorini, L. Gatignon, E. Gersabeck, A. Gianoli, S. Giudici, E. Goudzovski, S. Goy Lopez, E. Gushchin, B. Hallgren, M. Hita-Hochgesand, E. Iacopini, E. Imbergamo, V. Kekelidze, K. Kleinknecht, V. Kozhuharov, V. Kurshetsov, G. Lamanna, C. Lazzeroni, M. Lenti, E. Leonardi, L. Litov, D. Madigozhin, A. Maier, I. Mannelli, F. Marchetto, P. Massarotti, M. Misheva, N. Molokanova, M. Moulson, S. Movchan, M. Napolitano, A. Norton, T. Numao, V. Obraztsov, V. Palladino, M. Pepe, A. Peters, F. Petrucci, B. Peyaud, R. Piandani, M. Piccini, G. Pierazzini, I. Popov, Yu. Potrebenikov, M. Raggi, B. Renk, F. Reti` ere, P. Riedler, A. Romano, P. Rubin, G. Ruggiero, A. Salamon, G. Saracino, M. SavriВґ e, V. Semenov, A. Sergi, M. Serra, S. Shkarovskiy, M. Sozzi, T. Spadaro, P. Valente, M. Veltri, S. Venditti, H. Wahl, R. Wanke, A. Winhart, R. Winston, O. Yushchenko, A. Zinchenko. 1 arXiv:1412.0240v1 [hep-ex] 30 Nov 2014 EPJ Web of Conferences will be set by the publisher DOI: will be set by the publisher c Owned by the authors, published by EDP Sciences, 2014 NA62 experiment at CERN SPS Venelin Kozhuharov1,2 , a 1 2 Laboratori Nazionali di Frascati - INFN, 40 E. Fermi, 00044 Frascati (Rome), Italy Faculty of Physics, University of Sofia вЂњSt. Kl. OhridskiвЂќ, 5 J. Bourchier Blvd., 1164 Sofia, Bulgaria Abstract. The NA62 experiment at SPS is a continuation of the long standing CERN kaon physics program. The high statistics and the unprecedent precision allow to probe the Standard Model and test the description of the strong interactions at low energy. The final results on the the lepton universality test by measuring the ratio RK = О“(K + в†’ e+ ОЅ)/О“(K + в†’ Вµ+ ОЅ) and the study of the K В± в†’ ПЂВ± ОіОі decay are presented. The major goal of the NA62 experiment is to perform a measurement of the Br(K + в†’ ПЂ+ ОЅВЇОЅ) with a precision of 10% in two years of data taking. The detector setup together with the analysis technique is described. 1 Introduction The high intensity approach of the fixed target experiments as opposed to the highest energy collisions provides a unique opportunity to address the Standard model through precision measurements. The phenomena in kaon physics allow to probe both the low energy behaviour of the strong interactions as well as the high energy weak scale through loop processes. Special attention should be given to the rare kaon decays since some of them could achieve sizeable contribution in the presence a e-mail: [email protected] Speaker, for the NA62 Collaboration: G. Aglieri Rinella, F. Ambrosino, B. Angelucci, A. Antonelli, G. Anzivino, R. Arcidiacono, I. Azhinenko, S. Balev, J. Bendotti, A. Biagioni, C. Biino, A. Bizzeti, T. Blazek, A. Blik, B. Bloch-Devaux, V. Bolotov, V. Bonaiuto, D. Britton, G. Britvich, N. Brook, F. Bucci, V. Buescher, F. Butin, E. Capitolo, C. Capoccia, T. Capussela, V. Carassiti, N. Cartiglia, A. Cassese, A. Catinaccio, A. Cecchetti, A. Ceccucci, P. Cenci, V. Cerny, C. Cerri, O. Chikilev, R. Ciaranfi, G. Collazuol, P. Cooke, P. Cooper, G. Corradi, E. Cortina Gil, F. Costantini, A. Cotta Ramusino, D. Coward, G. DвЂ™Agostini, J. Dainton, P. Dalpiaz, H. Danielsson, J. Degrange, N. De Simone, D. Di Filippo, L. Di Lella, N. Dixon, N. Doble, V. Duk, V. Elsha, J. Engelfried, V. Falaleev, R. Fantechi, L. Federici, M. Fiorini, J. Fry, A. Fucci, S. Gallorini, L. Gatignon, A. Gianoli, S. Giudici, L. Glonti, A. Goncalves Martins, F. Gonnella, E. Goudzovski, R. Guida, E. Gushchin, F. Hahn, B. Hallgren, H. Heath, F. Herman, E. Iacopini, O. Jamet, P. Jarron, K. Kampf, J. Kaplon, V. Karjavin, V. Kekelidze, A. Khudyakov, Yu. Kiryushin, K. Kleinknecht, A. Kluge, M. Koval, V. Kozhuharov, M. Krivda, J. Kunze, G. Lamanna, C. Lazzeroni, R. Leitner, R. Lenci, M. Lenti, E. Leonardi, P. Lichard, R. Lietava, L. Litov, D. Lomidze, A. Lonardo, N. Lurkin, D. Madigozhin, G. Maire, A. Makarov, I. Mannelli, G. Man- nocchi, A. Mapelli, F. Marchetto, P. Massarotti, K. Massri, P. Matak, G. Mazza, E. Menichetti, M. Mirra, M. Misheva, N. Molokanova, J. Morant, M. Morel, M. Moulson, S. Movchan, D. Munday, M. Napolitano, F. Newson, A. Norton, M. Noy, G. Nuessle, V. Obraztsov, S. Padolski, R. Page, V. Palladino, A. Pardons, E. Pedreschi, M. Pepe, F. Perez Gomez, F. Petrucci, R. Piandani, M. Piccini, J. Pinzino, M. Pivanti, I. Polenkevich, I. Popov, Yu. Potrebenikov, D. Protopopescu, F. Raffaelli, M. Raggi, P. Riedler, A. Romano, P. Rubin, G. Ruggiero, V. Russo, V. Ryjov, A. Salamon, G. Salina, V. Sam- sonov, E. Santovetti, G. Saracino, F. Sargeni, S. Schifano, V. Semenov, A. Sergi, M. Serra, S. Shkarovskiy, A. Sotnikov, V. Sougonyaev, M. Sozzi, T. Spadaro, F. Spinella, R. Staley, M. Statera, P. Sutcliffe, N. Szilasi, D. Tagnani, M. Valdata-Nappi, P. Valente, V. Vassilieva, B. Velghe, M. Veltri, S. Venditti, M. Vormstein, H. Wahl, R. Wanke, P. Wertelaers, A. Winhart, R. Winston, B. Wrona, O. Yushchenko, M. Zamkovsky, A. Zinchenko EUROPEAN ORGANISATION FOR NUCLEAR RESEARCH (CERN) arXiv:1412.0237v1 [hep-ex] 30 Nov 2014 CERN-PH-EP-2014-158 Submitted to: JHEP Search for anomalous production of prompt same-sign lepton pairs and pair-produced doubly charged Higgs bosons with в€љ s = 8 TeV pp collisions using the ATLAS detector The ATLAS Collaboration Abstract A low-background inclusive search for new physics in events with same-sign dileptons is presented. The search uses protonвЂ“proton collisions corresponding to 20.3 fbв€’1 of integrated luminosity taken in 2012 at a centre-of-mass energy of 8 TeV with the ATLAS detector at the LHC. Pairs of isolated leptons with the same electric charge and large transverse momenta of the type eВ± eВ± , eВ± ВµВ± , and ВµВ± ВµВ± are selected and their invariant mass distribution is examined. No excess of events above the expected level of Standard Model background is found. The results are used to set upper limits on the cross sections for processes beyond the Standard Model. Limits are placed as a function of th e dilepton invariant mass within a fiducial region corresponding to the signal event selection criteria. Exclusion limits are also derived for a specific model of doubly charged Higgs boson production. c 2014 CERN for the benefit of the ATLAS Collaboration. Reproduction of this article or parts of it is allowed as specified in the CC-BY-3.0 license. arXiv:1412.0227v1 [hep-ex] 30 Nov 2014 Measurement of the fraction of top quark pair events produced via gluon-gluon fusion at the Tevatron in lepton+jets final states Sungwoong Choa , Suyong Choia , Sehwook Leea , JaeHoon Lima , and SungWoo Younb a Korea University, b University of Maryland E-mail: [email protected] Abstract. We report a measurement в€љ of the fraction of top quark pair events produced via s = 1.96 TeV in lepton+jets final states using the gluon-gluon fusion in pВЇ p collisions at full RunII data set corresponding to 9.7 fbв€’1 of integrated luminosity collected by the DГ� experiment. We utilize a boosted decision tree to distinguish top quark pair events produced by q qВЇ annihilation and gg fusion. We perform a template fit to extract the ttВЇ production fraction via gg fusion and find fgg = 0.096 В± 0.039 (stat.) +0.077 в€’0.062 (syst.). 1. Introduction The standard model (SM) predicts that at the Tevatron ttВЇ events are produced predominantly by either quark-antiquark (q qВЇ) annihilation and gg fusion with fractions of в‰€ 85% and в‰€ 15%, respectively. However, this prediction for the fraction of ttВЇ production from gg fusion can vary from 10% to 20% due to uncertainties on the parton density functions (PDF) [1] [2]. A precise measurement of this quantity will be helpful to have better understanding of the structure of proton. Since different production mechanisms can result in significantly different kinematic properties [3], a deviation from the SM calculations may also suggest the possible existence of new physics. The top quark, with a mass of about 175 GeV/c2 , has a life time that is an order of magnitude smaller than the typical quantum chromodynamics (QCD) hadronization time of в‰€ 5 Г— 10в€’24 s [4]. As a consequence, the spin information of the top quark is preserved to its decay particles. Due to different spin structures for different production modes, the angular distributions of decay particles are useful to distinguish between q qВЇ annihilation and gg fusion events. Furthermore, the gluon has a large degrees of freedom in color charge state than a quark does, the former is involved with the QCD effects such as initial/final state radiations more than the latter, resulting in, for example, extra partons and thus affecting the kinematic distributions of the final state particles. To separate ttВЇ events produced through q qВЇ annihilation and gg fusion, we utilize the boosted decision tree (BDT) [5] in the toolkit for multivariate analysis method with ROOT (TMVA) package. We use 16 input variables sensitive to the production mechanism, which will be described in Sec. 2. We construct the BDT templates from simulated events for q qВЇ annihilation arXiv:1412.0181v1 [hep-ex] 30 Nov 2014 Search for a light charged Higgs boson decaying into csВЇ at CMS Gouranga Koleв€—вЂ Tata Institute of Fundamental Research Homi Bhabha Road, Colaba Mumbai 400005, India E-mail: [email protected] We present results on the search for a light charged Higgs boson that can be produced in the decay of a top quark and later decays into a charm and an antistrange quark. The analysis is performed using 19.7 fbв€’1 pp collison data recorded with the CMS detector at LHC. Prospects for Charged Higgs Discovery at Colliders - CHARGED 2014, 16-18 September 2014 Uppsala University, Sweden в€— Speaker. вЂ On behalf of the CMS Collaboration c Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. Search for H + в†’ csВЇ at CMS http://pos.sissa.it/ Gouranga Kole 1. Introduction A Higgs boson has recently been discovered by ATLAS [1] and CMS [2] with a mass close to 125 GeV and properties, within uncertainties of the available data, consistent with those expected from the standard model (SM). Although this would complete the SM, still the latter cannot be the full story having many missing links such as dark matter, baryon asymmetry and gravity. Several extensions to the SM have been proposed to address these inconsistent features. The minimal supersymmetric standard model (MSSM) is one such model that contains two Higgs doublets, resulting in five physical Higgs states: a light and heavy CP-even h and H, a CP-odd A, and two charged Higgs bosons H В± . At tree level, the MSSM Higgs sector can be expressed in terms of two parameters, which are usually chosen to be the mass of the CP-odd Higgs boson (mA ) and the ratio of the vacuum expectation values of the two Higgs doublets (tan ОІ ). The lower limit on the charged Higgs boson mass is 78.6 GeV, as determined by LEP experiments [3, 4]. If the mass of the charged Higgs boson is smaller than the mass difference between the top and the bottom quarks, the top can decay via t в†’ H + b. For tan ОІ < 1, the charged Higgs boson preferentially decays to a charm and an antistrange quark (cs). ВЇ In the two Higgs doublet model of type I and Y the branching fraction B(H + в†’ cs) ВЇ is larger than 10% for any value of tan ОІ , while in type II and X it can reach up to 100% for tan ОІ < 1 [5]. In this study, we assume B(H + в†’ cs) ВЇ to be 100%. Recently ATLAS has set an upper limit on B(t в†’ H + b) between 5% and 1% for charged Higgs masses in the range 90-150 GeV [6]. The presence of the t в†’ H + b, H + в†’ csВЇ decay channel alters the event yield for t tВЇ pairs having hadronic jets in the final state, compared to the SM prediction. The search for a charged Higgs ВЇ where boson is thus sensitive to the decays of the top pairs t tВЇ в†’ H В± bW в€“ bВЇ and t tВЇ в†’ H В± bH в€“ b, the charged Higgs boson decays into a charm and an antistrange quark. We perform a model independent search [7] for the charged Higgs boson in the t tВЇ в†’ H В± bW в€“ bВЇ в†’ Вµ + ETmiss + jets final state, where the W boson decays to a muon and a neutrino (leading to missing transverse energy ETmiss ) and the H + decays to cs. ВЇ The contribution of the process t tВЇ в†’ H В± bH в€“ bВЇ is expected to be negligible in the above final state. Figure 1 shows the dominant Feynman diagrams for this final state both in the SM t tВЇ process as well as the same in presence of the H + boson. 2. CMS Detector and Object Reconstruction The distinguishing features of the CMS detector [8] are a 6 m long solenoidal magnet that produces 3.8 T magnetic field, a fully silicon-based tracking device, a PbWO4 crystal electromagnetic calorimeter, a brass-scintilltor sandwich hadron calorimeter, and an excellent muon system. All physics objects used in the analysis are reconstructed with the particle flow (PF) algorithm, essentially combining information from the aforementioned subdectectors. Muons are reconstructed by matching the tracks in the silicon tracker with the hits in the muon system. Jets are reconstructed based on the anti-kT algorithm with a cone radius parameter R = 0.5. The ETmiss is defined as the negative vector sum of the transverse momenta (pT ) of all PF candidates. To identify jets originating from a b quark, we apply the b-jet identification criteria that involve the use of secondary vertices together with track-based lifetime information. 2 arXiv:1412.0139v1 [hep-ex] 29 Nov 2014 Experimental results on ttВЇ + W/Z/Оі and SM top couplings from the Tevatron and the LHC Tamara VВґ azquez SchrВЁ oder for the ATLAS, CDF, CMS and D0 Collaborations II. Physikalisches Institut, Georg-August UniversitВЁ at GВЁ ottingen, GВЁ ottingen, Germany E-mail: [email protected] Abstract. Experimental results from the CDF and D0 Collaborations at the Tevatron and the ATLAS and CMS Collaborations at the LHC on the processes related to probing top quark couplings are presented. Evidence of both ttВЇZ and ttВЇW processes is reported. All measurements are in agreement with the SM expectations. 1. Motivation The top quark was discovered in 1995 by the CDF and D0 Collaborations [1, 2]. It couples to the Standard Model fields through its gauge and Yukawa interactions. Some of these couplings have been investigated at the Tevatron, through studies of the W tb vertex and the ttВЇОі production, while others, such as the ttВЇZ and ttВЇH production, are becoming accessible only with the high statistics top quark sample at the LHC, also called for this reason a вЂ�top quark factoryвЂ™. At hadron colliders, the first evidence of the coupling of the top quark to the Оі, Z, and H boson will come from the production rate, while constraints on the coupling of the top quark with the W boson come from both the top quark decay and the single top production. Given its large mass, the top quark may play a special role in the electroweak symmetry breaking (EWSB) and therefore, new physics related to EWSB may be found first in top quark precision measurements. Possible new physics signals would cause deviations of the top quark couplings tZ, tОі, and W tb, from the SM prediction. 2. Wtb coupling Information on the coupling of the top quark to the W boson can be obtained from the top quark decay and electroweak single top production. 2.1. W-helicity measurements Since the top quark decays almost exclusively as t в†’ W + b, the measurement of the W boson helicity in top decays probes the structure of the W tb vertex, which in the Standard Model (SM) is V-A. Since W bosons are produced as on-shell particles in top quark decays, their polarisation can be longitudinal, left-handed or right-handed. The fractions with a certain polarisation, F0 , FL and FR , can be extracted from measurements of the angular distribution of arXiv:1412.0106v1 [hep-ex] 29 Nov 2014 Measurement of Top-Quark Polarization in t-channel Single-Top Production Matthias Komm Centre for Cosmology, Particle Physics and Phenomenology, UniversitВґe catholique de Louvain, 1348 Louvain-la-Neuve, Belgium E-mail: [email protected] Abstract. The measurement of the top quark polarization, sensitive to the electroweak coupling structure, in t-channel single-top production is presented. Events are analyzed corresponding to an integrated luminosity of approximately 20 fbв€’1 recorded with the CMS в€љ detector during pp collisions at s = 8 TeV. By requiring one isolated lepton (muon or electron), two jets, and missing transverse energy, an angular asymmetry, sensitive to the polarization of the top quark, is reconstructed in the top-quark rest frame. The corresponding angular asymmetry at parton level is inferred from data in a phase space with enhanced singletop t-channel candidates through unfolding. Remaining background contributions are estimated through a ML-fit and subtracted. A polarization of Pt = 0.82 В± 0.12 (stat.) В± 0.32 (syst.) is measured assuming a spin-analyzing power of the charged lepton stemming from the top decay of 100%. 1. Introduction In the theory of particle physics, the Standard Model (SM), electroweak interactions between fermions via charged currents are maximally parity violating. Only left-handed fermions (or right-handed anti-fermions) can couple to W bosons through a V-A coupling structure. The top quark offers an unique possibility amongst all quarks to probe this prediction because of its very short lifetime below the hadronization time scale. Therefore, its spin orientation stays encoded in the angular distribution of its decay products. An observable sensitive to the electroweak top quark coupling structure is given in t-channel single top-quark production by the forward-backward asymmetry (top) A= N (cos Оёl,q (top) N (cos Оёl,q (top) > 0) в€’ N (cos Оёl,q > 0) + (top) (top) N (cos Оёl,q < 0) 1 = Pt О±l 2 < 0) (1) in the top-quark rest frame, where Оёl,q denotes the angle between the lepton and the light (u, d, s, c) quark which may also be referred to as spectator quark. The polarization, Pt , denotes the alignment of the top-quark spin with the light-quark momentum and the spin-analyzing power, О±l , quantifies the alignment of lepton with the top-quark spin. Theoretical calculations show that the particular V-A structure leads to a high polarization, Pt = 0.98, and spin analyzing power О±l = 1 [1]. arXiv:1412.0104v1 [hep-ex] 29 Nov 2014 Experimental results with boosted top quarks in the final state Johannes Erdmann for the ATLAS and CMS collaborations Technische UniversitВЁ at Dortmund, FakultВЁ at Physik, Experimentalphysik IV, Otto-Hahn-StraГџe 4, 44227 Dortmund, Germany E-mail: [email protected] в€љ Abstract. An overview of analyses using data at s = 7 TeV and 8 TeV of proton-proton collisions at the LHC is presented. These analyses use boosted techniques to search for new phenomena involving top quarks and to measure the production of top quarks at high transverse momenta. Such techniques involve top-quark tagging algorithms, boson-tagging algorithms, and strategies for b-tagging and lepton identification in the environment where the top quark decay products are close to each other. The strategies are optimized for the different final states and for different ranges of the transverse momenta of the particles involved, improving on traditional resolved analysis strategies. 1. Introduction в€љ With roughly 5 fbв€’1 of LHC proton-proton (pp) collision data at s = 7 TeV and roughly 20 fbв€’1 at 8 TeV available for analysis, the ATLAS and CMS collaborations are facing the challenge of identifying top quarks in the boosted regime with top-tagging techniques [1] (toptagging). The traditional resolved strategy of identifying individual jets originating from the decay of hadronically decaying top quarks fails for Lorentz boosts of the top quark for which the decay products overlap in О·вЂ“П† space. With the use of larger jet radii, however, all decay products of hadronically decaying top quark may be contained in one single jet (large-R jets). The substructure of such jets can be used to distinguish the three-prong decay of the top quark from the background processes, in particular from jets originating from light quarks or gluons. Similar strategies are used for the identification of hadronic decays of W , Z and Higgs bosons (boson-tagging): W в†’ q qВЇ , Z в†’ q qВЇ and H в†’ bВЇb. The identification of jets originating from b-quarks, is more challenging in the boosted regime, because of nearby activity in the tracking detector and the high transverse momentum of b-quarks. The application of b-tagging to small-R subjets of the large-R jet (subjet b-tagging), however, improves the performance of the top-tagging algorithms, and allows for multiple b-tags inside a single large-R jet as used in the identification of hadronically decaying Higgs bosons. Moreover, lepton identification is more challenging in the boosted regime, because nearby activity renders traditional isolation criteria inefficient. Hence, analyses using leptons often make use of modified lepton-isolation criteria. The top-tagging, boson-tagging and b-tagging strategies used by the ATLAS and CMS collaborations in the boosted regime are described in several documents [2, 3, 4, 5, 6], where also predictions from Monte Carlo (MC) simulations are compared to pp collision data. CERN-PH-TH-2014-232 Towards realistic models from Higher-Dimensional theories with Fuzzy extra dimensionsв€— arXiv:1412.0438v1 [hep-th] 1 Dec 2014 D.Gavriil1 , G.Manolakos1 , G.Zoupanos1,2 1 Physics Department, National Technical University, Zografou Campus, GR-15780 Athens, Greece 2 Theory Group, Physics Department Cern, Geneva, Switzerland E-mails: [email protected] , [email protected] , [email protected] Abstract We briefly review the Coset Space Dimensional Reduction (CSDR) programme and the best model constructed so far and then we present some details of the corresponding programme in the case that the extra dimensions are considered to be fuzzy. In particular, we present a four-dimensional N = 4 Super Yang Mills Theory, orbifolded by Z3 , which mimics the behaviour of a dimensionally reduced N = 1, 10-dimensional gauge theory over a set of fuzzy spheres at intermediate high scales and leads to the trinification GUT SU (3)3 at slightly lower, which in turn can be spontaneously broken to the MSSM in low scales. Keywords: coset space dimensional reduction, unification, fuzzy spheres, orbifold projection 1 Introduction enter the theory, because of the ad hoc introduction of the Higgs and Yukawa sectors, is a major problem demanding solution. This embarrassment can be overcome by considering that those sectors originate from a higher dimensional theory. Various frameworks starting with the Coset Space Dimensional Reduction (CSDR) [21вЂ“23] and the Scherk-Schwarz [24] reduction schemes suggest that unification of the gauge and Higgs sectors can take place making use of higher dimensions. This means that the four-dimensional gauge and Higgs fields are the surviving components of the reduction procedure of the gauge fields of a pure higher-dimensional gauge theory. Furthermore, the addition of fermions in the higher-dimensional gauge theory leads naturally (after CSDR) to Yukawa couplings in four dimensions. The last step in this unified description in high dimensions is to relate the gauge and fermion fields, which can be achieved by demanding that the higher-dimensional gauge theory is N = 1 supersymmetric, i.e. the gauge and fermion fields are members of the same vector supermultiplet. In order to maintain an N = 1 supersymmetry after dimensional reduction, Calabi-Yau (CY) manifolds Since 1970вЂ™s there has been an intense pursuit of unification, that is the establishment of a single theoretical model describing all interactions. Profound research activity has resulted in two very interesting frameworks, namely Superstring Theories [1] and Non-Commutative Geometry [2]. Both approaches, although developing independently, share common unification targets and aim at exhibiting improved renormalization properties in the ultraviolet regime as compared to ordinary field theories. Moreover, these two (initially) different frameworks were bridged together after realizing that a Non-Commutative gauge theory can describe the effective physics on D-branes whilst a non-vanishing background antisymmetric field is present [3]. Significant progress has recently been made regarding the dimensional reduction of the E8 Г— E8 Heterotic String using non-symmetric coset spaces [4][20], in the presence of background fluxes and gaugino condensates. It is widely known that the large number of Standard ModelвЂ™s free parameters which в€— Based on a talk presented at the International Conference "Quantum Field Theory and Gravity (QFTGвЂ™14)" (Tomsk, July 28 - August 3, 2014) by G.Z. (invited main speaker). 1 arXiv:1412.0407v1 [astro-ph.CO] 1 Dec 2014 Fitting BICEP2 with defects, primordial gravitational waves and dust Joanes Lizarraga1 , Jon Urrestilla1 , David Daverio2 , Mark Hindmarsh3,4 , Martin Kunz2,5 , Andrew R. Liddle6 1 Department of Theoretical Physics, University of the Basque Country UPV/EHU, 48080 Bilbao, Spain 2 DВґepartement de Physique ThВґeorique & Center for Astroparticle Physics, UniversitВґe de Gen`eve, Quai E. Ansermet 24, CH-1211 Gen`eve 4, Switzerland 3 Department of Physics & Astronomy, University of Sussex, Brighton, BN1 9QH, United Kingdom 4 Department of Physics and Helsinki Institute of Physics, PL 64, FI-00014 University of Helsinki, Finland 5 African Institute for Mathematical Sciences, 6 Melrose Road, Muizenberg, 7945, South Africa 6 Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ, United Kingdom E-mail: [email protected] Abstract. In this work we discuss the possibility of cosmic defects being responsible for the B-mode signal measured by the BICEP2 collaboration. We also allow for the presence of other cosmological sources of B-modes such as inflationary gravitational waves and polarized dust foregrounds, which might contribute to or dominate the signal. On the one hand, we find that defects alone give a poor fit to the data points. On the other, we find that defects help to improve the fit at higher multipoles when they are considered alongside inflationary gravitational waves or polarized dust. Finally, we derive new defect constraints from models combining defects and dust. This proceeding is based on previous works [1, 2]. 1. Introduction The recent detection of B-mode polarization on large angular scales [3] has opened a new window to test and constrain models that predict primordial perturbations. The leading candidate, as claimed by the BICEP2 team, is primordial inflationary gravitational waves. For a tensorto-scalar ratio r of around 0.2, these give a good match to the spectral shape in the region в‰€ [40 150]. An alternative mechanism of generating primordial B-modes is the presence of cosmic defects. Even though their relative contribution to the temperature power spectrum is expected to be sub-dominant, they can still contribute importantly to the B-mode polarization. We explore whether cosmic defects could explain or help other primary contributors fit the data better. Recently some works have reported that the measurements made by BICEP2 can have a nonnegligible astrophysical source: polarized dust foregrounds [4, 5, 6]. We extended our primary analysis including such a possible source. Hyperfine Interactions manuscript No. (will be inserted by the editor) Pion-assisted N в€† and в€†в€† dibaryons, and beyond arXiv:1412.0198v1 [nucl-th] 30 Nov 2014 Avraham Gal Received: date / Accepted: date Abstract Experimental evidence for I(J P )=0(3+ ) в€†в€† dibaryon D03 (2370) has been presented recently by the WASA-at-COSY Collaboration. Here I review new hadronic-basis Faddeev calculations of L = 0 nonstrange pionassisted N в€† and в€†в€† dibaryon candidates. These calculations are so far the only ones to reproduce the relatively small D03 (2370) width of 70вЂ“80 MeV. Predictions are also given for the location and width of D30 , the I(J P )=3(0+ ) exotic partner of D03 (2370). Extensions to strangeness S=в€’1 dibaryons are briefly discussed. Keywords Faddeev equations В· nucleon-nucleon interactions В· pion-baryon interactions В· dibaryons PACS 11.80.Jy, 13.75.Cs, 13.75.Gx, 21.45.-v 1 Introduction The WASA-at-COSY Collaboration has presented recently striking evidence for a I(J P ) = 0(3+ ) в€†в€† dibaryon some 80вЂ“90 MeV below the в€†в€† threshold, with a relatively small width of О“ в‰€ 70 в€’ 80 MeV, by observing a distinct resonance in the energy spectrum of pn в†’ dПЂПЂ reactions [1,2] as shown in Fig. 1вЂ“left. Isospin I = 0 is uniquely fixed in this particular ПЂ 0 ПЂ 0 production reaction and the spin-parity 3+ assignment follows from the measured deuteron and pions angular distributions, assuming s-wave decaying в€†в€† pair. The shape 2 of the Mв€љ dПЂ distribution on the right panel supports в€†в€† assignment and its peak at s в‰€ 2.13 GeV, almost at the D12 (2150) N в€† dibaryon location (see below), might suggest a possible role for D12 in forming the в€†в€† dibaryon D03 . A. Gal Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel E-mail: [email protected] Shape of the inflaton potential and the efficiency of the universe heating A.D. Dolgov,1, 2, 3, в€— A.V. Popov,4, вЂ and A.S. Rudenko1, 5, вЂЎ 1 Novosibirsk State University, Novosibirsk, 630090, Russia ITEP, Bol. Cheremushkinskaya ul., 25, 113259 Moscow, Russia 3 Dipartimento di Fisica e Scienze della Terra, Universit` a degli Studi di Ferrara Polo Scientifico e Tecnologico - Edificio C, Via Saragat 1, 44122 Ferrara, Italy 4 Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Troitsk, Moscow, 142190 Russia 5 Budker Institute of Nuclear Physics, Novosibirsk, 630090, Russia arXiv:1412.0112v1 [astro-ph.CO] 29 Nov 2014 2 It is shown that the efficiency of the universe heating by an inflaton field depends not only on the possible presence of parametric resonance in production of scalar particles but also strongly depends on the shape of the oscillations of the inflaton around its equilibrium point. In particular, when the inflaton oscillations deviate from pure harmonic one towards a succession of step functions, the production probability rises by several orders of magnitude. This in turn leads to a higher temperature of the universe after inflaton decay. An example of the inflaton potential, which leads to such type of the field behavior and sufficiently long inflation, is presented. I. INTRODUCTION The cosmological inflation included, roughly speaking, the following two epochs. The first one was a quasiexponential expansion, when the Hubble parameter, H, slowly changed with time and the universe expanded by a huge factor, eN where N= Hdt в‰« 1. (1.1) During this period the Hubble parameter exceeded the inflaton mass or, better to say, the condition was fulfilled H2 > d2 U (П†) в‰Ў |U вЂІвЂІ (П†)| , dП†2 (1.2) where U (П†) is the potential of the inflaton field, П†. Due to the large Hubble friction (see eq. (3.3)) during this time, the field П† remained almost constant slowly moving in the direction of the вЂќforceвЂќ (в€’U вЂІ ). The second stage began when H 2 dropped below |U вЂІвЂІ | and lasted till the inflaton field reached the equilibrium value at U вЂІ (П†eq ) = 0. It is usually assumed that П†eq = 0 and U (П†eq ) = 0 to avoid nonzero vacuum energy. During this period П† oscillated around П†eq producing elementary particles, mostly with masses below the frequency of the inflaton oscillations. This was a relatively short period which may be called big bang, when the initial vacuum-like state exploded, creating the primeval cosmological plasma. The process of the universe heating was first studied in refs. [1вЂ“3] within the framework of perturbation theory. A non-perturbative approach was pioneered in refs. [4, 5]. In both these papers a possibility of excitation of parametric resonance, which might grossly enhance the particle (boson) production rate was mentioned. In the model of ref. [4] parametric resonance could not be effectively induced because of the red-shift and scattering of the produced particles which were dragged out of the resonance zone and the main attention in this work was dedicated to non-perturbative production of fermions. However, the resonance may be effective if it is sufficiently wide. In this case the particle production rate can be strongly enhanced [5, 6]. As is well known, parametric resonance exists for bosons only. In quantum language, it can be understood as Bose amplification of particle production due to presence of identical bosons in the final state, the same phenomena as the laser induced radiation. For bosons there can be another phenomenon leading to very fast and strong excitation of the bosonic field coupled to inflaton, if the effective mass squared of such field would be negative (tachyonic situation). It might naturally happen for sufficiently large and negative product gП†, see below eqs. (2.1, 2.2). This is the Higgs-like effect, when vacuum state becomes unstable. Both phenomena are absent in the case of fermion production. Imaginary mass of fermions breaks hermicity of the Lagrangian, so tachyons must be absent. As for parametric resonance, it is not present in the fermionic в€— Electronic address: [email protected] address: [email protected]ru вЂЎ Electronic address: [email protected] вЂ Electronic Noname manuscript No. (will be inserted by the editor) Fundamental cosmology in the E-ELT era: The status and future role of tests of fundamental coupling stability arXiv:1412.0108v1 [astro-ph.CO] 29 Nov 2014 C.J.A.P. Martins Received: date / Accepted: date Abstract The observational evidence for the recent acceleration of the universe demonstrates that canonical theories of cosmology and particle physics are incompleteвЂ”if not incorrectвЂ”and that new physics is out there, waiting to be discovered. The most fundamental task for the next generation of astrophysical facilities is therefore to search for, identify and ultimately characterise this new physics. Here we highlight recent efforts along these lines, mostly focusing on ongoing work by CAUPвЂ™s Dark Side Team aiming to develop some of the science case and optimise observational strategies for forthcoming facilities. The discussion is centred on tests of the stability of fundamental couplings (since the provide a direct handle on new physics), but synergies with other probes are also briefly considered. The goal is to show how a new generation of precision consistency tests of the standard paradigm will soon become possible. Keywords Observational cosmology В· Fundamental physics В· Fundamental couplings В· Dark energy В· Astronomical facilities 1 Introduction In the middle of the XIX century Urbain Le Verrier and others mathematically discovered two new planets by insisting that the observed orbits of Uranus and Mercury agree with the predictions of Newtonian physics. The first of theseвЂ”which we now call NeptuneвЂ”was soon observed by Johann Galle and Heinrich dвЂ™Arrest. However, the second (dubbed Vulcan) was never found. We now know that the discrepancies in MercuryвЂ™s orbit were a consequence of the fact that Newtonian physics canвЂ™t adC.J.A.P. Martins CAUP and IA-Porto, Rua das Estrelas s/n, 4150-762 Porto, Portugal Tel.: +351-226089891 Fax: +351-226089831 E-mail: [email protected] Chiral symmetry and effective field theories for hadronic, nuclear and stellar matter Jeremy W. Holta , Mannque Rhob,c , Wolfram Weised,e a Department of Physics, University of Washington, Seattle, 98195, USA of Physics, Hanyang University, Seoul 133-791, Korea c Institut de Physique ThВґ eorique, CEA Saclay, 91191 Gif-sur-Yvette, France d Physik Department, Technische UniversitВЁ at MВЁ unchen, D-85747 Garching, Germany e ECT в€— , Villa Tambosi, I-38123 Villazzano (TN), Italy b Department arXiv:1411.6681v1 [nucl-th] 24 Nov 2014 Abstract Chiral symmetry, first entering in nuclear physics in the 1970вЂ™s for which Gerry Brown played a seminal role, has led to a stunningly successful framework for describing strongly-correlated nuclear dynamics both in finite and infinite systems. We review how the early, germinal idea conceived with the soft-pion theorems in the pre-QCD era has evolved into a highly predictive theoretical framework for nuclear physics, aptly assessed by Steven Weinberg: вЂњit (chiral effective field theory) allows one to show in a fairly convincing way that what they (nuclear physicists) have been doing all along ... is the correct first step in a consistent approximation scheme.вЂќ Our review recounts both how the theory presently fares in confronting Nature and how one can understand its extremely intricate workings in terms of the multifaceted aspects of chiral symmetry, namely, chiral perturbation theory, skyrmions, Landau Fermi-liquid theory, the Cheshire cat phenomenon, and hidden local and mended symmetries. Keywords: Contents 1 Prologue 3 2 Introductory survey 4 2.1 2.2 Low-energy QCD and chiral symmetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1.1 Chiral symmetry and the pion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1.2 Pseudoscalar meson spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Chiral effective field theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2.1 The Nambu-Goldstone boson sector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2.2 The baryon sector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2.3 Chiral pion-nucleon effective Lagrangian . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3 Chiral symmetry and hadron structure 11 3.1 From little bag to chiral bag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.2 Encoding chiral symmetry and confinement in the chiral bag . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.2.1 13 Leakage of baryon charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preprint submitted to Physics Reports November 26, 2014 Inflation in R2 supergravity with non-minimal superpotentials G. A. Diamandis, B. C. Georgalas, K. Kaskavelis, P. Kouroumalou,, A. B. Lahanas,в€— and G. Pavlopoulos arXiv:1411.5785v1 [hep-th] 21 Nov 2014 University of Athens, Physics Department, Nuclear and Particle Physics Section, GRвЂ“15771 Athens, Greece We investigate the cosmological inflation in a class of supergravity models that are generalizations of non-supersymmetric R2 models. Although such models have been extensively studied recently, especially after the launch of the PLANCK and BICEP2 data, the class of models that can be constructed has not been exhausted. In this note, working in a supergravity model that is a generalization of CecottiвЂ™s model, we show that the appearance of new superpotential terms, which are quadratic in the superfield О› that couples to the Ricci supermultiplet, alters substantially the form of the scalar potential. The arising potential has the form of the Starobinsky potential times a factor that is exponential in the inflaton field and dominates for large inflaton values. We show that the well-known Starobinsky inflation scenario is maintained only for unnaturally small fine-tuned values of the coupling describing the О›2 superpotential terms. A welcome feature is the possible improvement of the tensor to scalar ratio r which however is not of the desired order of magnitude to agree with the BICEP2 data if all observational constraints are taken into account. Keywords: Supergravity, Cosmology, Modified Theories of Gravity, Relativity and Gravitation PACS: 04.65.+e, 98.80.-k, 04.50.Kd, 95.30.Sf I. INTRODUCTION Models of inflation are constrained by recent observations of WMAP [1] and Planck [2] satellites. The spectral index is found in the range ns = 0.9608 В± 0.0054 while the tensor to scalar ratio is bounded from above r < 0.111. Moreover the BICEP2 [4] experiment claims discovery of primordial gravitational waves +0.06 resulting to a ratio r = 0.16в€’0.05 which, if finally confirmed, is a challenge for both experimentalists and theorists. PLANCK satellite data [2] are in perfect agreement with the Starobinsky model of inflation [3] which predicts a tensor to scalar ratio in the range r 0.004, which is almost two orders of magnitude smaller than the claimed discovery of BICEP2 which points towards chaotic inflation [5] . Much effort has been expended towards building inflationary models embedded in the framework of supergravity theories. Chaotic inflation [5] scenario can be incorporated in supergravity schemes [6, 7] and more recently general chaotic inflationary supergravity potentials have been studied [8]. Supergravity models that incorporate R + R2 terms and reproduce StarobinskyвЂ™s inflation predictions for r, ns have received a lot of attention recently[9вЂ“33]. A class of supergravity models are described by no-scale KВЁahler potentials [34] and many of the proposed inflationary models have a no-scale structure [10, 11, 15, 22, 26, 27, 30, 33]. It is worth noting that in this class of models there is the possibility of accommodating models interpolating between low ( r в€ј 0.001) and large values ( r в€ј 0.1) depending on the parameters. This can be also accomplished in attractor solutions that relate in a continuous manner the predictions of the Starobinsky model with those of the quadratic chaotic potential [35, 36]. Among the possible theoretical schemes, incorporating the virtues of the Starobinsky R2 model that lead to successful inflation, are higher derivative supergravity Lagrangians [37вЂ“39]. In these, besides the matter chiral and vector multiplets, additional chiral multiplets are unavoidably introduced. In the minimal scenario [38] one uses two multiplets that after eliminations of the auxiliary fields involved leads to a supergravity Lagrangian including R2 . This extends the Starobinsky model in a non-trivial manner в€— Electronic address: [email protected] Prepared for submission to JCAP arXiv:1407.7123v2 [astro-ph.CO] 28 Nov 2014 Parameter estimation with Sandage-Loeb test Jia-Jia Geng,a Jing-Fei Zhang,a Xin Zhanga,b,1 a Department of Physics, College of Sciences, Northeastern University, Shenyang 110004, China b Center for High Energy Physics, Peking University, Beijing 100080, China E-mail: [email protected], [email protected], [email protected] Abstract. The Sandage-Loeb (SL) test directly measures the expansion rate of the universe in the redshift range of 2 z 5 by detecting redshift drift in the spectra of Lyman-О± forest of distant quasars. We discuss the impact of the future SL test data on parameter estimation for the О›CDM, the wCDM, and the w0 wa CDM models. To avoid the potential inconsistency with other observational data, we take the best-fitting dark energy model constrained by the current observations as the fiducial model to produce 30 mock SL test data. The SL test data provide an important supplement to the other dark energy probes, since they are extremely helpful in breaking the existing parameter degeneracies. We show that the strong degeneracy between в„¦m and H0 in all the three dark energy models is well broken by the SL test. Compared to the current combined data of type Ia supernovae, baryon acoustic oscillation, cosmic microwave background, and Hubble constant, the 30-yr observation of SL test could improve the constraints on в„¦m and H0 by more than 60% for all the three models. But the SL test can only moderately improve the constraint on the equation of state of dark energy. We show that a 30-yr observation of SL test could help improve the constraint on constant w by about 25%, and improve the constraints on w0 and wa by about 20% and 15%, respectively. We also quantify the constraining power of the SL test in the future highprecision joint geometric constraints on dark energy. The mock future supernova and baryon acoustic oscillation data are simulated based on the space-based project JDEM. We find that the 30-yr observation of SL test would help improve the measurement precision of в„¦m , H0 , and wa by more than 70%, 20%, and 60%, respectively, for the w0 wa CDM model. 1 Corresponding author. Identification of Observables for Quark and Gluon Orbital Angular Momentum Aurore Courtoy,1, в€— Gary R. Goldstein,2, вЂ J. Osvaldo Gonzalez Hernandez,3, вЂЎ Simonetta Liuti,4, В§ and Abha Rajan5, В¶ arXiv:1412.0647v1 [hep-ph] 1 Dec 2014 1 IFPA, AGO Department, UniversitВґe de Li`ege, BЛ† at. B5, Sart Tilman B-4000 Li`ege, Belgium and nstituto de Fsica, Universidad Nacional Autnoma de Mxico, A.P. 20-364, Mxico 01000, D.F., Mxico. 2 Department of Physics and Astronomy, Tufts University, Medford, MA 02155 USA. 3 Istituto Nazionale di Fisica Nucleare (INFN) - Sezione di Torino via P. Giuria, 1, 10125 Torino, ITALY, Italy 4 University of Virginia - Physics Department, 382 McCormick Rd., Charlottesville, Virginia 22904 - USA and INFN, Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044, Frascati RM, Italy. 5 University of Virginia - Physics Department, 382 McCormick Rd., Charlottesville, Virginia 22904 - USA A new debate has recently arisen on the subject of orbital angular momentum in QCD, in particular, on its observability, and on its partonic interpretation. Orbital momentum can be defined in QCD using two different decomposition schemes that yield a kinetic and a canonical definition, respectively. We argue that kinetic orbital angular momentum is intrinsically associated with twist three generalized parton distributions, and it is therefore more readily observable, while, due to parity constraints, canonical angular momentum, if defined as suggested in the literature in terms of generalized transverse momentum distributions, cannot be observed in scattering processes involving a single hadronic reaction plane. PACS numbers: 13.60.Hb, 13.40.Gp, 24.85.+p The question of the observability of Orbital Angular Momentum (OAM) in QCD was recently addressed in Ref.[1]. The main thrust of the paper was to identify an observable from DVCS experiments for OAM as given by the second moment of the twist-3 GPD, G2 [2, 4]. Alongside with this identification, some difficulties were pointed out which are inherent with the alternative definition of OAM in terms of Generalized Transverse Momentum Distributions (GTMDs), concerning especially the way these objects would be measured in deeply virtual exclusive scattering processes from the proton. This triggered a series of observations in Ref.[5], related to the treatment of parity transformations in Ref.[1], some of which we believe are ill-founded. This situation, given the important issues at stake, i.e. the definition of OAM in QCD, and the possibility of measuring it, necessitates therefore an additional explanation. The recent discussion follows in the steps of a debate which was initiated previously (see Refs.[6, 7] for reviews) on the gauge invariant decomposition of the total quark and gluon angular momenta, J q , and J g , into their respective spin and orbital components. One of the results out of this discussion was that it became clear that OAM could be defined through a twist three contribution from the relation [2, 3], dx x Gq2 (x, 0, 0) = 1 в€’ 2 dxx(H q (x, 0, 0) + E q (x, 0, 0)) + dxH q (x, 0, 0) в†’ dx x Gq2 (x, 0, 0) = в€’Lq , (1) where Gq2 is a specific twist three Generalized Parton Distribution (GPD) appearing in the parametrization of the quark-quark correlation function [2, 4, 8, 9] (G2 was renamed E2T in the full classification of GPDs given in Ref.[10]); H q , E q , and H q are the twist two GPDs contributing to the observables for Deeply Virtual Compton Scattering (DVCS) processes introduced in [11] (see reviews in Refs.[12, 13]. Lq is referred to as kinetic [7] or mechanical [6] OAM, it appears in the relation [11], 1 1 в€†ОЈ + Lq + J g = , 2 2 and it is at variance with the canonical OAM, Lq,g can which is defined through the decomposition [14], 1 1 = в€†ОЈ + Lqcan + в€†G + Lgcan . 2 2 в€— Electronic address: [email protected] address: [email protected] вЂЎ Electronic address: [email protected] В§ Electronic address: [email protected] В¶ Electronic address: [email protected] 1 In our previous paper we used the notation L = Lq q can . вЂ Electronic (2) 1 (3) MT 2 to the Rescue вЂ“ Searching for Sleptons in Compressed Spectra at the LHC Zhenyu Han Institute for Theoretical Science, University of Oregon, Eugene, OR 97403, USA Yandong Liu arXiv:1412.0618v1 [hep-ph] 1 Dec 2014 Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China We propose a novel method for probing sleptons in compressed spectra at hadron colliders. The process under study is slepton pair production in R-parity conserving supersymmetry, where the slepton decays to a neutralino LSP of mass close to the slepton mass. In order to pass the trigger and obtain large missing energy, an energetic mono-jet is required. Both leptons need to be detected in order to suppress large standard model backgrounds with one charged lepton. We study variables that can be used to distinguish the signal from the remaining major backgrounds, which include ttВЇ, W W +jet, Z+jet, and single top production. We find that the dilepton mT 2 , bound by the mass difference, can be used as an upper bound to efficiently reduce the backgrounds. It is estimated that sleptons with masses up to about 150 GeV can be discovered at the 14 TeV LHC with 100 fbв€’1 integrated luminosity. 1 I. INTRODUCTION Low energy supersymmetry (SUSY) is an attractive theory of physics beyond the standard model (SM). In order to avoid fine tuning to the Higgs mass, super partners of the SM particles are predicted to be around or below the TeV scale, which is often dubbed вЂњnatural supersymmetryвЂќ вЂ“ see Ref. [1] and references therein. However, SUSY searches at the large hadron collider (LHC) have not revealed any signal beyond the standard model, which have put stringent constraints on the SUSY mass spectrum. To reconcile the null results with supersymmetry, one either (partially) gives up naturalness and accepts that the super particlesвЂ™ masses are beyond the current reach of the 8 TeV LHC (which could, however, be discovered at 14 TeV or a future collider), or assumes SUSY particles are light and accessible, but the signal is hidden in the SM backgrounds. In order not to miss the SUSY signals, both the two possibilities should be explored. One way to hide light SUSY particles is to make the spectrum compressed, that is, the mass splittings among the SUSY particles are so small that the decay products of the SUSY cascades are soft. The signal events that contain such soft particles, including jets, leptons or photons, are difficult to trigger on, and even if recorded, they are usually buried in SM backgrounds. Special search strategies are required to find the signal events and previous studies include those on a light stop [2вЂ“5], a light sbottom [6] and light electroweakinos [7вЂ“12]. In this article, we focus on another important SUSY process, slepton pair production. We assume the lightest supersymmetric particle (LSP) is a neutralino with mass around 100 GeV. A light slepton with mass close to the LSP mass is not required by naturalness because its loop contribution to the Higgs mass is small. Nevertheless a 5 в€ј 20 GeV mass splitting, which we assume in this article, is certainly possible without вЂњfine-tuningвЂќ model parameters. Moreover, such a small splitting is needed to obtain the correct relic density in the co-annihilation scenario [13]. When sleptons are pair produced and each of which decays to a neutralino, we have two soft leptons and missing energy in a signal event. The major SM backgrounds include ttВЇ, W W +jet, Z(в†’)П„ П„ +jet and single top production. In order to pass the trigger, we require an extra hard jet and large missing energy to be present in the event. This is also the final state particles considered in Refs. [10, 12], where the discovery potential of the LHC for quasi-degenerate Higgsinos is explored.A crucial observation in the analysis which makes the discovery possible is the fact that the majority of the lepton pairs are produced through off-shell Z s in П‡02 в†’ П‡01 decays, and the dilepton invariant mass m is bound from above by the П‡02 в€’ П‡01 mass difference. Therefore, we can apply an upper cut on m to eliminate bulk of the background events, while retaining most of the signal events. This feature is unfortunately absent for slepton pair production because the two leptons necessarily come from two different decay chains. For a typical 10 GeV lepton pT acceptance cut, the dilepton invariant mass spreads from в€ј 10 GeV to в€ј 80 GeV, which significantly overlaps with the SM backgrounds. Clearly, a different strategy is needed. In this article, we propose a novel method for searching slepton pairs in a compressed spectrum. In order to exploit the small mass splitting, we consider the mT 2 variable defined from the two leptons and the missing transverse momentum. This variable, to a good approximation, is bound by the mass difference between the slepton and the LSP. Because of this property, we use it as an upper bound in our method. This is in contrast to the traditional use of mT 2 in SUSY searches, where mT 2 is a variable alternative to the missing transverse momentum and usually used as a lower Few-Body Systems manuscript No. (will be inserted by the editor) V.A. Karmanov В· J. Carbonell arXiv:1412.0590v1 [hep-ph] 1 Dec 2014 Current conservation in electrodisintegration of a bound system in the Bethe-Salpeter approach Received: date / Accepted: date Abstract Using our solutions of the Bethe-Salpeter equation with OBE kernel in Minkowski space both for the bound and scattering states, we calculate the transition form factors for electrodisintegration of the bound system which determine the electromagnetic current J of this process. Special emphasis is put on verifying the gauge invariance which should manifest itself in the current conservation. We find that for any value of the momentum transfer q the contributions of the plane wave and the final state interaction to the quantity J В· q cancel each other thus providing J В· q = 0. However, this cancellation is obtained only if the initial Bethe-Salpeter amplitude (bound state), the final one (scattering state) and the current operator are strictly consistent with each other. A reliable result for the transition form factor can be found only in this case. Keywords Bethe-Salpeter equation В· Electromagnetic current В· Electromagnetic form factors 1 Introduction Bethe-Salpeter (BS) equation [1] provides an efficient theoretical framework to describe bound and scattering states of a relativistic system. Finding its solution is complicated by the singularities in the integrand of the equation as well as by the singular character of the amplitude itself. To avoid this difficulty, one can perform Wick rotation [2] and transform the BS equation in the Euclidean form. However, the Wick rotation cannot be performed in the integral for electromagnetic (e.m.) form factors (see e.g. [3]). Therefore, to calculate form factors, we need the BS solution in Minkowski space. In finding these solutions, an important progress was achieved in the recent years using different and independent methods (see [4] for a brief review). In one of these methods [5] the kernel of the BS equation is approximately represented in a separable form. This allows to perform more advanced analytical calculations and therefore simplifies finding solutions and form factors. Another method is based on representing the BS amplitude via the Nakanishi integral [6] both for bound [7; 8; 9; 10; 11] and scattering [12] states. The elastic e.m. form factor in this method was calculated in [13]. Recently we developed a method [14] based on the direct treatment of singularities of the BS equation. Both the bound and scattering state amplitudes in Minkowski space were found. They allow to calculate [15] the electrodisintegration of the bound system, i.e., form factor of the transition: bound в†’ scattering state. The contribution of the final state interaction (FSI) to this form factor is given by V.A. Karmanov Lebedev Physical Institute, Leninsky Prospekt 53, 119991 Moscow, Russia E-mail: [email protected] J. Carbonell Institut de Physique NuclВґeaire, UniversitВґe Paris-Sud, IN2P3-CNRS, 91406 Orsay Cedex, France Chiral Superfluidity for QCD T. Kalaydzhyanв€— Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800, U.S.A. arXiv:1412.0536v1 [hep-ph] 1 Dec 2014 Abstract We argue that the strongly coupled quark-gluon plasma formed at LHC and RHIC can be considered as a chiral superfluid. The вЂњnormalвЂќ component of the fluid is the thermalized matter in common sense, while the вЂњsuperfluidвЂќ part consists of long wavelength (chiral) fermionic states moving independently. We use the bosonization procedure with a finite cut-off and obtain a dynamical axion-like field out of the chiral fermionic modes. Then we use relativistic hydrodynamics for macroscopic description of the effective theory obtained after the bosonization. Finally, solving the hydrodynamic equations in gradient expansion, we find that in the presence of external electromagnetic fields or rotation the motion of the вЂњsuperfluidвЂќ component gives rise to the chiral magnetic, chiral vortical, chiral electric and dipole wave effects. Latter two effects are specific for a two-component fluid, which provides us with crucial experimental tests of the model. Introduction The non-trivial structure of the QCD vacuum attracted much attention in light of recent heavyion experiments performed at RHIC and LHC. These experiments make it possible to study the strongly-coupled quark-gluon plasma (sQGP) in hadronic scale magnetic fields [1]. The non-trivial gluonic configurations may induce an imbalance between densities of left- and righthanded light quarks (chirality). As a strong magnetic field is applied to the system, the imbalance can give rise to a net electric current in sQGP along the magnetic field (chiral magnetic effect [2, 3]). So far it was difficult to build a first-principles theory, describing this and similar effects, since the physics of sQGP is essentially nonperturbative. However, there is a need in such a theory, because constant axial chemical potentials, introduced by hand, break unitarity [4] and lead to various consistency and stability problems [5, 6]. At the same time, without the knowledge of all possible anomalous effects of a similar kind, one will face difficulties in the experimental searches for each of them. Fortunately, it seems that such a theory can be established (and it is sketched below), because QCD contains a long-wave axion-like degree of freedom, which can play a role of carrier for the chirality. Indeed, one can consider QCD coupled to QED with an auxiliary gauged UA (1), and bosonize quarks with Dirac eigenvalues smaller than some fixed scale О›. Since there is no gauge UA (1) in nature, one can choose a pure gauge form of the external axial vector field and, as a result of the procedure, one obtains the в€— e-mail: [email protected] 1 Prepared for submission to JHEP arXiv:1412.0520v1 [hep-ph] 1 Dec 2014 Classification of effective operators for interactions between the Standard Model and dark matter M. Duch,a B. Grzadkowski a b a J. Wudkab Faculty of Physics, University of Warsaw, HoЛ™za 69, 00-681 Warsaw, Poland Department of Physics and Astronomy, UC Riverside, Riverside, CA 92521, USA E-mail: [email protected], [email protected], [email protected] Abstract: We construct a basis for effective operators responsible for interactions between the Standard Model and a dark sector composed of particles with spin в‰¤ 1. Redundant operators are eliminated using dim-4 equations of motion. We consider simple scenarios where the dark matter components are stabilized against decay by вќ©2 symmetries. We determine operators which are loop-generated within an underlying theory and those that are potentially tree-level generated. Impact of О·c hadroproduction data on charmonium production and polarization within NRQCD framework Hong-Fei Zhang1 , Zhan Sun2 , Wen-Long Sang3 , and Rong Li4 1 arXiv:1412.0508v1 [hep-ph] 1 Dec 2014 3 Department of Physics, School of Biomedical Engineering, Third Military Medical University, Chongqing 400038, China. 2 Department of Physics, Chongqing University, Chongqing 401331, P.R. China School of Physical Science and Technology, Southwest University, Chongqing 400700, China 4 Department of Applied Physics, XiвЂ™an Jiaotong University, XiвЂ™an 710049, China (Dated: December 2, 2014) With the recent LHCb data on О·c production and based on heavy quark spin symmetry, we obtain the long-distance matrix elements for both О·c and J/П€ productions, among which, the color-singlet one for О·c is obtained directly by the fit of experiment for the first time. Using our long-distance matrix elements, we can provide good description of the О·c and J/П€ hadroproduction measurements. Our predictions on J/П€ polarization are in good agreement with the LHCb data and pass through the two sets of CDF measurements in medium pt region. Considering all the possible uncertainties carefully, we obtained quite narrow bands of the J/П€ polarization curves. PACS numbers: 12.38.Bx, 12.39.St, 13.85.Ni, 14.40.Pq Nonrelativistic QCD (NRQCD) factorization framework [1] has gained its reputation from the success in many processes, among which, heavy quarkonia hadroproduction [2вЂ“4] is one of the most remarkable examples. Moreover, several groups have accomplished their computer programs for the calculation of QCD corrections to quarkonium related processes. QCD next-toleading order (NLO) predictions [5вЂ“10] based on NRQCD achieved good agreement with almost all the experimental measurements on quarkonia hadroproduction. However, for the J/П€ case, one is still suffering from the ambiguity caused by the freedom in the determination of the color-octet (CO) long-distance matrix elements (LDMEs) [5вЂ“7, 10вЂ“13]. In addition, the J/П€ polarization puzzle is another challenge that NRQCD is facing. Despite that three groups [11вЂ“13] have made great efforts to proceed the calculation to NLO in О±s , none of their CO LDMEs can reproduce the recent LHCb data [14, 15] with good precision. On the other hand, many works [3, 4, 16, 17] have proceeded their concerns to the processes in which no experimental data can be used to extract the LDMEs. There, they estimate these LDMEs based on heavy quark spin symmetry (HQSS) and velocity scaling rule (VSR). Nevertheless, the proof of NRQCD factorization does not require the two rules [18, 19], hence, the phenomenological test of them is urgent. Recently, LHCb data [20] on О·c produciton came out and provided an opportunity to further investigate these problems. Ref. [21, 22] studied direct О·c hadroproduction at leading order (LO) in О±s within NRQCD framework, [8] however, missing the 1 S0 channel. Since only inclusive and prompt О·c production rate has been measured, one should also consider contributions from hc feeddown, the asymptotic behavior of which, in large transverse momentum (pt ) limit, scales as pв€’6 t . According to our previous work [17], the contribution of this part is negligible comparing with experimental data. Feeddown contribu- tions from other excited cВЇ c bound states are even smaller than that from hc , so that they are not under our consideration. For direct О·c production, up to the order of v 4 , where v is the typical relative velocity of the constituent quark and antiquark in the quarkonium, four [1] [8] [8] [8] channels (1 S0 , 1 S0 , 3 S1 , 1 P1 ) are involved. Among [8] them, 3 S1 channel scales as pв€’4 in large pt limit, while t the other three scale as pв€’6 . Moreover, the NLO QCD t corrections to all the channels are not significant, which indicates good convergence in О±s expansion. Therefore, [8] it is possible to determine OО·c (3 S1 ) precisely by the fit of the experimental data. Further, we can assume HQSS and fix the other two CO LDMEs for О·c produciton as well as those for J/П€ production, and see whether they are able to provide reasonable descriptions of J/П€ production and polarization. Noticing that, in Ref. [6, 12, 13], the LDMEs obtained by minimizing П‡2 do not indicate the VSR, we give up employing this rule as the basis of our arguement. We should also notice that the values of the produc[1] [1] tion LDMEs OО·c (1 S0 ) and OJ/П€ (3 S1 ) have never been obtained directly from the fit of experiment; only the values of the decay ones have been extracted from experiment. The production LDMEs are considered to be the same as the decay ones in the sense of VSR, the importance of the higher order effects of which is not clear. Since the absolute values of the CS LDMEs play a very important role in the exclusive double charmonia production in e+ eв€’ collisions, high-precision determination of them would be urgent. LHCb data on О·c production rate provides an opportunity to obtain the value of [1] OО·c (1 S0 ) by fitting experimental data. As a result, precise evaluation of the short-distance coefficient (SDC) [1] of 1 S0 channel is necessary, and our calculation will be accurate to NLO in О±s as well as in v 2 , while, higher order corrections are neglected. We should also consider the uncertainty caused by the possible large logarithmic arXiv:1412.0503v1 [hep-ph] 1 Dec 2014 Heavy flavours in high-energy nuclear collisions: quenching, flow and correlations A. BeraudoвЂ , A. De Pace, M. Monteno, M. Nardi, F. Prino INFN, sezione di Torino, Via Pietro Giuria 1, I-10125 Torino E-mail: вЂ [email protected] Abstract. We present results for the quenching, elliptic flow and azimuthal correlations of heavy flavour particles in high-energy nucleus-nucleus collisions obtained through the POWLANG transport setup, developed in the past to study the propagation of heavy quarks in the Quark-Gluon Plasma and here extended to include a modeling of their hadronization in the presence of a medium. Hadronization is described as occurring via the fragmentation of strings with endpoints given by the heavy (anti-)quark Q(Q) and a thermal parton q(q) from the medium. The flow of the light quarks is shown to affect significantly the RAA and v2 of the final D mesons, leading to a better agreement with the experimental data. Heavy quarks вЂ“ indirectly accessible through D-mesons, heavy-flavour decay electrons and muons and J/П€вЂ™s from B decays вЂ“ have been used for a long time as probes of the medium formed in heavy-ion collisions. In a series of papers [1, 2, 3] over the last few years we developed a complete setup (referred to as POWLANG) for the study of heavy flavour observables in highenergy nucleus-nucleus collisions, describing the initial hard production of the QQ pairs and the corresponding parton-shower stage through the POWHEG-BOX package [4, 5] and addressing the successive evolution in the plasma through the relativistic Langevin equation. Here we present a brief summary of our recent efforts aimed at supplementing the above numerical tool by modeling the hadronization of the heavy quarks accounting for the presence of a surrounding medium made of light thermal partons feeling the collective flow of the fluid: a comprehensive exposition can be found in [6]. In order to simulate the hadronization of heavy quarks in the medium at the end of their propagation in the QGP we proceed as follows. Once a heavy quark Q, during its stochastic propagation in the fireball, has reached a fluid cell below the decoupling temperature Tdec , it is forced to hadronize. One extracts then a light antiquark q light (up, down or strange, with relative thermal abundances dictated by the ratio m/Tdec ) from a thermal momentum distribution corresponding to the temperature Tdec in the Local Rest Frame (LRF) of the fluid; information on the local fluid four-velocity uВµfluid provided by hydrodynamics allows one to boost the momentum of q light from the LRF to the laboratory frame. A string is then constructed joining the endpoints given by Q and q light and is then passed to PYTHIA 6.4 [7] to simulate its fragmentation into hadrons (and their final decays). In agreement with PYTHIA, in evaluating their momentum distribution, light quarks are taken as вЂњdressedвЂќ particles with the effective masses mu/d = 0.33 GeV and ms = 0.5 GeV. Concerning Tdec the values 0.155 and 0.17 GeV are explored. In the following some representative results obtained with the new hadronization procedure are displayed and compared to experimental data (when available). EPJ Web of Conferences will be set by the publisher DOI: will be set by the publisher c Owned by the authors, published by EDP Sciences, 2014 Possible Implication of a Single Nonextensive pT Distribution for Hadron Production in High-Energy pp Collisions в‹† Cheuk-Yin Wong1 , a , Grzegorz Wilk2 , b , Leonardo J. L. Cirto3 , c , Constantino Tsallis2,4 , d arXiv:1412.0474v1 [hep-ph] 1 Dec 2014 1 Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA National Centre for Nuclear Research, Warsaw 00-681, Poland 3 Centro Brasileiro de Pesquisas Fisicas & National Institute of Science and Technology for Complex Systems, Rua Xavier Sigaud 150, 22290-180 Rio de Janeiro-RJ, Brazil 4 Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA 2 Abstract. Multiparticle production processes in pp collisions at the central rapidity region are usually considered to be divided into independent "soft" and "hard" components. The first is described by exponential (thermal-like) transverse momentum spectra in the low-pT region with a scale parameter T associated with the temperature of the hadronizing system. The second is governed by a power-like distributions of transverse momenta with power index n at high-pT associated with the hard scattering between partons. We show that the hard-scattering integral can be approximated as a nonextensive distribution of a quasi-power-law containing a scale parameter T and a power index n = 1/(qв€’1), where q is the nonextensivity parameter. We demonstrate that the whole region of transverse momenta presently measurable at LHC experiments at central rapidity (in which the observed cross sections varies by 14 orders of magnitude down to the low pT region) can be adequately described by a single nonextensive distribution. These results suggest the dominance of the hard-scattering hadron-production process and the approximate validity of a вЂњno-hair" statistical-mechanical description of the pT spectra for the whole pT region at central rapidity for pp collisions at high-energies. 1 Introduction Particle production in pp collisions comprises of many different mechanisms in different parts of the phase space. We shall be interested in particle production in the central rapidity region where it is customary to divide the multiparticle production into independent soft and hard processes populating different parts of the transverse momentum space separated by a momentum scale p0 . As a rule of thumb, the spectra of the soft processes in the low-pT region are (almost) exponential, F(pT )в€јexp(в€’pT /T ), and are usually associated with the thermodynamical description of the hadronizing system, the fragmentation of a flux tube with a transverse dimension, or the production of particles by the Schwinger mechanism [1вЂ“5]. The pT spectra of the hard process in the high-pT region are regarded as essentially power-like, F(pT )в€јpв€’n T , and are usually associated with the hard scattering process [6вЂ“10]. However, it was found already long time ago that both description could be replaced by simple interpolating formula [11], F(pT ) = A 1 + pT p0 в‹† Presented by G.Wilk a e-mail: [email protected] b e-mail: [email protected] c e-mail: [email protected] d e-mail: [email protected] в€’n , (1) that becomes power-like for high pT and exponential-like for low pT . Notice that for high pT , where we are usually neglecting the constant term, the scale parameter p0 becomes irrelevant, whereas for low pT it becomes, together with power index n, an effective temperature T = p0 /n. The same formula re-emerged later to become known as the QCD-based Hagedorn formula [12]. It was used for the first time in the analysis of UA1 experimental data [13] and it became one of the standard phenomenological formulas for pT data analysis. In the mean time it was realized that Eq. (1) is just another realization of the nonextensive distribution [14] with parameters q and T , and a normalization constant A, F (pT ) = A 1 в€’ (1 в€’ q) pT T 1/(1в€’q) , (2) that has been widely used in many other branches of physics. For our purposes, both formulas are equivalent with the identification of n = 1/(qв€’1) and p0 = nT , and we shall use them interchangeably. Because Eq. (2) describes nonextensive systems in statistical mechanics, the parameter q is usually called the nonextensivity parameter. As one can see, Eq. (2) becomes the usual Boltzmann-Gibbs exponential distribution for q в†’ 1, with T becoming the temperature. Both Eqs. (1) and (2) have been widely used Nuclear Physics A Nuclear Physics A 00 (2014) 1вЂ“8 arXiv:1412.0471v1 [hep-ph] 1 Dec 2014 Initial state in relativistic nuclear collisions and Color Glass Condensate FranВёcois Gelis Institut de Physique ThВґeorique, CEA/Saclay, 91191 Gif sur Yvette cedex, France Abstract In this talk, I discuss recent works related to the pre-hydrodynamical stages of ultra-relativistic heavy ion collisions. Keywords: Heavy Ion Collisions, Color Glass Condensate, Initial State 1. Introduction Hydrodynamical models are very successful at reproducing bulk observables in high energy heavy ion collisions. However, it is a long standing puzzle to understand from the underlying Quantum Chromodynamics (QCD) why this description is so effective. Indeed, the description of the early stages of heavy ion collisions which is most closely related to QCD вЂ“the Color Glass Condensate (CGC) frameworkвЂ“ predicts at the very beginning of the fireball evolution a situation which is very different from a quasi perfect fluid. The purpose of this talk is to discuss recent works aiming at a first principles CGC description of the early stages of heavy ion collisions, where by вЂњearly stagesвЂќ we mean the pre-hydrodynamical evolution (left part of fig. 1). Ultimately, the goal is to have a description of these early stages that explains how the hydrodynamical behavior develops and that matches smoothly into hydrodynamics (right part of fig. 1), in such a way that the time П„0 at which the switching happens becomes unessential (in the same spirit as a factorization scale for parton distributions). Note PL / PT t +1 freeze out Pre-Hydro hadrons kinetic theory gluons & quarks in eq. time viscous hydro П„0 gluons & quarks out of eq. strong fields classical dynamics Hydro z -1 Figure 1. Left: stages of a heavy ion collision. Right: matching to hydrodynamics. 1 Calibrating Analytical Models for Semilocal Strings arXiv:1412.0432v1 [hep-ph] 1 Dec 2014 A. Lopez-Eiguren1 Department of Theoretical Physics, University of the Basque Country UPV-EHU, 48040 Bilbao, Spain E-mail: [email protected] Abstract. In this work we calibrate two different analytic models of semilocal strings by constraining the values of their free parameters. In order to do so, we use data obtained from the largest and most accurate field theory simulations of semilocal strings to date, and compare several key properties with the predictions of the models. As this is still work in progress, we present some preliminary results together with descriptions of the methodology we are using in the characterisation of semilocal string networks. 1. Introduction Understanding the evolution of string networks is crucial for predicting their number densities, which in turn determine their potentially observable effects. However, the quantitatively accurate modelling of string network evolution is a difficult problem, requiring the combination of a range of techniques (both numerical and analytical), and interpolating between physics at very different energy scales. Here, we present a calibration of analytical models for semilocal strings using field theory simulations. This work is part of an ongoing project where we tackle in turn different aspects of the calibration procedure by comparing the numerical simulations with predictions for the analytic models. Firstly, in section 3, we study the large-scale properties of the simulated networks [1]. Then, in section 4, we outline the comparison between field theory simulations and the analytic models, anticipating work that will appear in [2]. Section 5 shows the last ingredient of our analysis, where we present the techniques we will use in a future work [3] to estimate the velocities of the semilocal strings. Prior to all this, in section 2 we introduce the semilocal model and the analytic models used in this work, as well as the numerical simulations performed. 2. The Model 2.1. Semilocal Model Semilocal strings [5, 6, 7] were introduced as a minimal extension of the Abelian Higgs (AH) model with two complex scalar fields instead of just one, that form an SU (2) doublet. This leads to U (1) flux-tube solutions even though the vacuum manifold is simply connected. The strings of this extended model have some similarities with ordinary local U (1) strings, but they are not purely topological and will therefore have different properties. For example, since they are not 1 Work in collaboration with A.AchВґ ucarro, A.Avgoustidis, A.M.M.Leite, C.J.A.P.Martins, A.S.Nunes, J.Urrestilla Nuclear Physics B Proceedings Supplement Nuclear Physics B Proceedings Supplement 00 (2014) 1вЂ“6 Radiative corrections to Higgs coupling constants in two Higgs doublet models Mariko Kikuchiв€— arXiv:1412.0375v1 [hep-ph] 1 Dec 2014 Department of Physics, University of Toyama, 3190 Gofuku, Toyama 930-8555, JAPAN Abstract A pattern of deviations in the Standard Model (SM) like Higgs boson (h) couplings from their SM predictions depends on the structure of the Higgs sector and the Yukawa interaction. In particular, in Two Higgs Doublet Models (THDMs) with a softly-broken Z2 symmetry, different characteristic patterns of deviation in Yukawa coupling constants (h f fВЇ) can be allowed depending on four types of Yukawa interactions. We calculate h f fВЇ coupling constants at the one-loop level in all the types of THDMs. Even if there is no deviation in the h f fВЇ couplings at the tree level, they can deviate from the SM predictions by a few percent due to extra Higgs boson loop contributions. We find that if the deviations in the gauge couplings hVV (V = Z, W) are found with an enough large to be measured at the International Linear Collider (ILC), the scale factors for the h f fВЇ couplings do not overlap among the THDMs with four types of Yukawa interactions even taking into account the radiative corrections. Therefore, in such a case, we can indirectly determine the type of the THDMs at the ILC even without information from direct searches of the additional Higgs bosons. Keywords: Extended Higgs sectors, Radiative corrections 1. Introduction Although the standard model (SM) like Higgs boson (h) was discovered at the LHC experiment [2, 3], a lot of things are still unknown in the Higgs sector: e.g., what is the origin of negative mass term in the SM Higgs potential, whether the Higgs field is an elementary field or a composite field. Furthermore, we have not yet understood the shape of the Higgs sector. The minimal Higgs sector of the SM is just an assumption. There is no principle that only one isospin doublet field must be present. There are possibilities that the Higgs sector is extended, and all extended Higgs sectors have not excluded at all by the data of the LHC. On the other hand, we can say that the structure of the Higgs sector is strongly related to a scenario of the new physics beyond the SM, because a lot of models based on those scenarios introduce extended the Higgs sectors. Determining the structure of в€— This talk is based on the collaboration with Shinya Kanemura and Kei Yagyu [1] the Higgs sector by bottom up approach is one of the most effective procedure to establish the new physics. In this talk, we consider a possibility to reconstruct the shape of the Higgs sector by coupling measurements of the SM like Higgs boson at future collider experiments. In general, in extended Higgs models, coupling constants of the SM like Higgs boson h deviate from the predictions in the SM due to two kinds of effects. One is the effect of field mixing. The other is the loop effect due to the extra Higgs bosons. A pattern of deviations in Higgs couplings depend on the number of the Higgs field, their representations and the mass of Higgs bosons in the loop. It is possible to discriminate extended Higgs sectors by using future precision data and comprehensively evaluating all coupling constants of h in each model. Within the в€љ relatively large uncertainties in the current LHC data ( s = 7, 8 TeV, the integrated luminosity (L) is about 25 fbв€’1 ), measured Higgs couplings seem to be consistent with the SM at both ATLAS в€љ [2] and CMS [3]. At the high luminosity LHC with s = 14 TeV and Baryon and lepton number violating effective operators in a non-universal extension of the Standard Model J. Fuentes-MartГn arXiv:1412.0370v1 [hep-ph] 1 Dec 2014 Instituto de FГsica Corpuscular, CSIC - Universitat de ValГЁncia, Apt. Correus 22085, E-46071 ValГЁncia, Spain Abstract. It is well known that non-abelian Yang-Mills theories present non-trivial minima of the action, the so-called instantons. In the context of electroweak theories these instanton solutions may induce violations of baryon and lepton number of the form в€†B = в€†L = n f , with n f being the number of families coupled to the gauge group. An interesting feature of these violations is that the flavor structure of the gauge couplings is inherited by the instanton transitions. This effect is generally neglected in the literature. We will show that the inclusion of flavor interactions in the instanton solutions may be interesting in certain theoretical frameworks and will provide an approach to include these effects. In particular we will perform this implementation in the non-universal SU(2)l вЉ— SU(2)h вЉ—U(1)Y model that singularizes the third family. Within this framework, we will use the instanton transitions to set a bound on the SU(2)h gauge coupling. Keywords: Baryon Number Violation, Lepton Number Violation, Non-perturbative effects PACS: 11.30.Fs, 11.30.Hv, 12.60.Cn INTRODUCTION It has been known for some time that baryon (B) and lepton (L) numbers are violated in the electroweak sector of the Standard Model (SM) due to anomalies [1, 2]. This violation takes place in such a way that, at lowest order, в€†B = в€†L = n f with n f the number of families coupled to the gauge group and therefore the quantity B в€’ L remains conserved. вЂ™t Hooft realized that the explicit violation of these global symmetries is due to classical gauge configurations with non-trivial topological charge [3, 4]. These gauge configurations are termed instantons and describe tunneling transitions between different inequivalent vacua. At zero temperature the potential barrier that separate the different vacua has a huge height, which gives rise to a suppression factor O exp в€’8ПЂ 2 /g2 for these B + L violating processes. It has been suggested that B + L violating processes might be unsuppressed in high-energy collisions [5] where the vacuum transitions, denoted now sphalerons, take place from above the potential barrier and therefore are free of the exponential suppression. The computation of these processes was done in Refs. [6, 7]. Unfortunately, the calculations performed in this direction violate the unitarity bound and therefore are unreliable. Even though the SM is in perfect agreement with the current experimental data, several theoretical and experimental issues need to be addressed. They have been extensively treated in the literature giving rise to many theories Beyond the Standard Model (BSM). Although low-energy instanton transitions are highly suppressed in the SM model this might no longer be true for BSM theories where the gauge couplings are larger. This possibility was explored in the framework of gauge non-universal models in Ref. [8] where the inclusion of flavor dynamics was missing in the calculation. This talk follows closely the work done in Ref. [9] and is devoted to the introduction of inter-family mixing in the one-instanton transitions. We will show that these effects are crucial in the calculation of proton decay observables and will present a systematic approach to its inclusion in the model. Once that the instanton-mediated baryon and lepton number violating amplitudes have been calculated, we will obtain an effective Lagrangian for these interactions that violates not only baryon and lepton number but also flavor. These operators will be used in order to constrain the gauge couplings from proton decay. For the sake of concreteness, we will perform this calculation in the non-universal SU(2)l вЉ— SU(2)h вЉ—U(1)Y model. However, many of the results presented here can be easily applied to other new physics models. Non-sterile electroweak-scale right-handed neutrinos and the dual nature of the 126-GeV scalar Vinh Hoang,1, в€— Pham Q. Hung,1, 2, вЂ and Ajinkya Shrish Kamat1, вЂЎ 1 arXiv:1412.0343v1 [hep-ph] 1 Dec 2014 2 Department of Physics, University of Virginia, Charlottesville, VA 22904-4714, USA Center for Theoretical and Computational Physics, Hue University College of Education, Hue, Vietnam (Dated: December 2, 2014) Can, and under which conditions, the 126-GeV SM-like scalar with the signal strengths for its decays into W + W в€’ , ZZ, ОіОі, bВЇb and П„ П„ВЇ being consistent with the SM predictions be accommodated in models that go beyond the Standard Model? Is it truly what it appears to be? A minimal extension of the original electroweak-scale right-handed neutrino model, in which right-handed neutrinos naturally obtain electroweak-scale masses, shows a scalar spectrum which includes the 126-GeV SM-like scalar possessing signal strengths compatible with experiment but also a dual nature quite unlike that of the Standard Model. In other words, the 126-GeV SM-like scalar could be an impostor. I. INTRODUCTION The discovery of the 126-GeV SM-like scalar [1] and the present absence of any new physics signals has opened up a whole host of questions as to the true nature of the electroweak symmetry breaking and to what may lie beyond the Standard Model. The sole existence of the 126GeV particle would leave unanswered several deep questions such as the origin of neutrino masses, the hierarchy of quark and lepton masses among many others. It also implies that the electroweak vacuum is metastable with drastic consequences in the very far-distant future [2]. It remains to be seen whether this most simple picture- albeit one with many question marks- will be the ultimate theory of nature or it is merely an effective theory at current accessible energies whose reality tests are incomplete and more non-SM phenomena will pop up in the not-too-distant future with Run II of the LHC. Despite the present lack of new physics at the LHC, it does not imply that it is not there. On the contrary, new physics has already appeared in the neutrino sector through neutrino oscillation and its implication on neutrino masses. This evidence, although quite clear, is only indirect and does not show where the new physics that gives rise to the aforementioned phenomena may appear. This difficulty in finding a direct evidence for the new physics involved in generating neutrino masses is compounded by the fact that these masses are so tiny, more than seven orders of magnitude smaller than the light- в€— вЂ вЂЎ [email protected] [email protected] [email protected] est lepton: the electron. In the most generic scenario of the elegant seesaw mechanism for generating tiny masses, the right-handed neutrinos are sterile i.e. singlets under the electroweak gauge group. In a nutshell, the two mass eigenvalues are m2D /M and M where the Dirac mass mD is proportional to the electroweak scale while the Majorana mass M is mD . In addition to the fact that ОЅR вЂ™s are assumed to be electroweak singlets, the very large values for M in a generic scenario makes it very very difficult to probe the crucial physics, namely that which gives rise to M which is responsible for the lightness of the вЂњactiveвЂќ neutrinos. Another facet of this new physics is the Majorana nature of the вЂњactiveвЂќ neutrinos themselves which could manifest itself through neutrino less double beta decays which so far have not been observed. Through neutrino oscillations, we have a hint of new physics but what it might be and where to look for it is still a big mystery at the present time. The aforementioned uncertainties rest in large part on the assumption that right-handed neutrinos are electroweak singlets. This usually comes from a certain extension of the SM such as the Left-Right symmetric model SU (2)L Г— SU (2)R Г— U (1)Bв€’L [3] or the Grand Unified model SO(10), among others. It goes without saying that the singlet assumption is not verified in the absence of experimental signals of right-handed neutrinos. If one is however willing to entertain the idea that right-handed neutrinos are not sterile, there is an entire panorama of accessible phenomena that can be searched for and studied. A non-sterile right-handed neutrino necessarily interacts with the electroweak gauge bosons and the Majorana mass term is expected to carry the electroweak quantum number and hence is proportional to The chiral magnetic effect in heavy-ion collisions from event-by-event anomalous hydrodynamics Yuji Hirono,1, в€— Tetsufumi Hirano,2 and Dmitri E. Kharzeev1, 3 1 Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA 2 Department of Physics, Sophia University, Tokyo 102-8554, Japan 3 Department of Physics, Brookhaven National Laboratory, Upton, New York 11973-5000, USA (Dated: December 2, 2014) The (3+1)D relativistic hydrodynamics with chiral anomaly is used to obtain a quantitative description of the chiral magnetic effect (CME) in heavy-ion collisions. We find that the chargedependent hadron azimuthal correlations are sensitive to the CME, and that the experimental observations are consistent with the presence of the effect. arXiv:1412.0311v1 [hep-ph] 1 Dec 2014 PACS numbers: The experimental study of charge-dependent hadron azimuthal correlations in heavy-ion collisions at RHIC [1, 2] and LHC [3] revealed a signal qualitatively consistent with the separation of electric charge predicted [4] as a signature of local P- and CP-odd fluctuations in QCD matter. The subsequent studies [5вЂ“7] improved the theoretical understanding of the underlying phenomenon вЂ“ the separation of electric charge in the quark-gluon plasma induced by the chirality imbalance in the presence of background magnetic field, or the вЂњchiral magnetic effectвЂќ (CME), see Ref. [8] for a review and additional references. The existence of CME has been confirmed in first-principle lattice QCDГ—QED simulations [9вЂ“12]. By holographic methods, the CME has also been found to persist at strong coupling [13], in accord with its nondissipative, topologically protected nature. Because the macroscopic behavior of matter at strong coupling is described by hydrodynamics, it is natural to address the question of the existence of CME within the framework of fluid dynamics. Son and Surowka [14] showed that the CME indeed is an integral part of relativistic hydrodynamics, and moreover its strength as fixed by the second law of thermodynamics is consistent with the field-theoretical prediction. The CME current in the hydrodynamic regime is carried by a novel collective gapless excitation, the chiral magnetic wave [15, 16]. Conformal anomalous hydrodynamics at second order in the derivative expansion has been formulated in [17]. Relativistic hydrodynamics with fluctuating initial conditions proved very successful in explaining the bulk of RHIC and LHC data (see Refs. [18вЂ“20] for recent reviews). It is thus appropriate to rely on this approach also for describing the CME in heavy-ion collisions, by using hydrodynamics with the terms induced by chiral anomaly and magnetic fields вЂ“ so-called anomalous hydrodynamics, or chiral magnetohydrodynamics (CMHD). The first pilot numerical study of anomalous hydrodynamics was performed in Ref. [21], where the effects of anomaly on the charge-dependent elliptic flow were investigated. Nevertheless, a fully quantitative description of the experimental data on charge-dependent azimuthal correlations has not been performed until now. In this Letter, we perform such a study basing on threedimensional ideal CMHD with event-by-event fluctuations in the initial conditions. Let us first describe the measured experimental observable [22] sensitive to the CME that we aim to describe. The azimuthal-angle distribution of observed particles reads dN О± в€ќ 1 + 2v1О± cos(П† в€’ ОЁRP ) + 2aО± 1 sin(П† в€’ ОЁRP ) dП† 2vnО± cos n(П† в€’ ОЁn ), + (1) n>1 where О± в€€ {+, в€’}. The Fourier coefficients vnВ± of the azimuthal-angle distribution characterize the shape of the produced matter in momentum space. The component with n = 1 is called the directed flow. In Eq. (1), we decomposed the directed flow into two directions, along FIG. 1: Schematic picture of a heavy-ion collision event in the transverse plane. B indicates the magnetic field, and J is the electric current induced by the chiral magnetic effect in the case of a positive initial axial charge density. The direction of J is flipped if the initial axial charge is negative. Next-to-leading Order Calculation for Jets Defined arXiv:1412.0298v1 [hep-ph] 30 Nov 2014 by a Maximized Jet Function Tom Kaufmann a , Asmita Mukherjee b , Werner Vogelsang a a Institute for Theoretical Physics, TВЁ ubingen University, Auf der Morgenstelle 14, 72076 TВЁ ubingen, Germany b Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India Abstract We present a next-to-leading order QCD calculation for the single-inclusive production of collimated jets at hadron colliders, when the jet is defined by maximizing a suitable jet function that depends on the momenta of final-state particles in the event. A jet algorithm of this type was initially proposed by Georgi and subsequently further developed into the class of вЂњJET algorithmsвЂќ. Our calculation establishes the infrared safety of the algorithms at this perturbative order. We derive analytical results for the relevant partonic cross sections. We discuss similarities and differences with respect to jets defined by cone or (anti-)kt algorithms and present numerical results for the Tevatron and the LHC. Jet quenching in pp and pA collisions в€— B.G. Zakharov1 arXiv:1412.0295v1 [hep-ph] 30 Nov 2014 1 L.D. Landau Institute for Theoretical Physics, GSP-1, 117940, Kosygina Str. 2, 117334 Moscow, Russia We study jet quenching in pp and pA collisions in the scenario with formation of a mini quark-gluon plasma. We find a significant suppression effect. For light hadrons at pT в€љ в€ј 10 GeV we obtained the reduction of the spectra by в€ј [20в€’30, 25в€’35, 30в€’40]% in pp collisions at s = [0.2, 2.76, 7] TeV. We discuss how jet quenching in pp collisions may change the predictions for the nuclear modification factors in AA collisions for light and heavy flavors. We also give predictions for modification of the photon-tagged and inclusive jet fragmentation functions in high multiplicity pp events. PACS numbers: I. INTRODUCTION One of the manifestation of the quark-gluon plasma (QGP) formation in AA collisions is the jet quenching phenomenon which is dominated by the radiative parton energy loss [1вЂ“7]. It leads to suppression of the high-pT spectra, which is characterized by the nuclear modification factor RAA given by the ratio of the inclusive cross section for AA collisions to the binary-scaled inclusive cross section for pp collisions RAA = dПѓ(AA в†’ hX)/dpT dy . Nbin dПѓ(pp в†’ hX)/dpT dy (1) It would be extremely interesting to observe jet quenching in pp and pA collisions, since it would be a direct signal of the mini-QGP formation. The QGP formation in pp and pA collisions have been addressed in several publications recently [8вЂ“10] from the viewpoint of the hydrodynamical flow effects. In recent papers [11, 12] we studied the possible manifestations of jet quenching in pp collisions within the lightcone path integral approach [3], which we previously used for analysis of jet quenching in AA collisions [13вЂ“16]. In [11] we discussed the medium modification of the Оі-tagged fragmentation functions (FFs) and in [12] the medium modification factor Rpp and its effect on the nuclear modification factors RAA and RpA . The medium modification factor Rpp characterizes the difference between the real inclusive pp cross section, accounting for the final-state jet interaction in the QGP, and the perturbative one, i.e., dПѓ(pp в†’ hX)/dpT dy = Rpp dПѓpert (pp в†’ hX)/dpT dy . (2) Since we cannot switch off the final state interaction in the QGP, the Rpp is not an observable quantity. Nevertheless, it may affect the theoretical predictions for RAA . Indeed, in the scenario with the QGP formation in pp collisions one should use in the denominator in (1) the real inclusive pp cross section which differs from the perturbative one. In this case one should compare with experimental RAA the following quantity: st RAA = RAA /Rpp , (3) st where RAA is the standard nuclear modification factor calculated using the pQCD predictions for the particle spectrum in pp collisions. The effect of the Rpp may be important for the centrality dependence of RAA and the azimuthal anisotropy (simply because in the scenario with the QGP formation in pp collisions О±s becomes bigger). It should also be important for the jet flavor tomography of the QGP [15вЂ“ 18]. Because the effect of Rpp on RAA for heavy quarks should be smaller due to weaker jet quenching for heavy quarks in pp collisions. In this talk I review the results of [11, 12] and extend the analysis [12] to heavy flavors. в€— Talk at XIth Quark Confinement and the Hadron Spectrum, Saint-Petersburg, Russia, 8-12 September 2014. Prepared for submission to JHEP arXiv:1412.0258v1 [hep-ph] 30 Nov 2014 The Higgs Portal Above Threshold Nathaniel Craig,a Hou Keong Lou,b Matthew McCullough,c and Arun Thalapillild a Department of Physics, University of California, Santa Barbara, CA 93106, USA Department of Physics, Princeton University, Princeton, NJ 08540, USA c Theory Division, CERN, 1211 Geneva 23, Switzerland d Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA b E-mail: [email protected], [email protected], [email protected], [email protected] Abstract: The discovery of the Higgs boson opens the door to new physics interacting via the Higgs Portal, including motivated scenarios relating to baryogenesis, dark matter, and electroweak naturalness. We systematically explore the collider signatures of singlet scalars produced via the Higgs Portal at the 14 TeV LHC and a prospective 100 TeV hadron collider. We focus on the challenging regime where the scalars are too heavy to be produced in the decays of an on-shell Higgs boson, and instead are produced primarily via an off-shell Higgs. Assuming these scalars escape the detector, promising channels include missing energy in association with vector boson fusion, monojets, and top pairs. We forecast the sensitivity of в€љ searches in these channels at s = 14 & 100 TeV and compare collider reach to the motivated parameter space of singlet-assisted electroweak baryogenesis, Higgs Portal dark matter, and neutral naturalness. ArXiv ePrint: 14xx.xxxx Average gluon and quark jet multiplicities A.V. Kotikov arXiv:1412.0224v1 [hep-ph] 30 Nov 2014 Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia Abstract. We show the results in [1, 2] for computing the QCD contributions to the scale evolution of average gluon and quark jet multiplicities. The new results came due a recent progress in timelike small-x resummation obtained in the MS factorization scheme. They depend on two nonperturbative parameters with clear and simple physical interpretations. A global fit of these two quantities to all available experimental data sets demonstrates by its goodness how our results solve a longstandig problem (5) of QCD. Including all the available theoretical input within our approach, О±s (Mz ) = 0.1199 В± 0.0026 has been obtained in the MS scheme in an approximation equivalent to next-to-next-to-leading order enhanced by the resummations of ln x terms through the NNLL level and of ln Q2 terms by the renormalization group. This result is in excellent agreement with the present world average. Keywords: Gluon and quark multiplicities, evolution, diagonalization PACS: 12.38.Cy, 12.39.St, 13.66.Bc, 13.87.Fh INTRODUCTION Collisions of particles and nuclei at high energies usually produce many hadrons and their production is a typical process where nonperturbative phenomena are involved. However, for particular observables, this problem can be avoided. In particular, the counting of hadrons in a jet that is initiated at a certain scale Q belongs to this class of observables. In this case, one can adopt with quite high accuracy the hypothesis of Local Parton-Hadron Duality (LPHD), which simply states that parton distributions are renormalized in the hadronization process without changing their shapes [3]. Hence, if the scale Q is large enough, this would in principle allow perturbative QCD to be predictive without the need to consider phenomenological models of hadronization. Nevertheless, such processes are dominated by soft-gluon emissions, and it is a well-known fact that, in such kinematic regions of phase space, fixed-order perturbation theory fails, rendering the usage of resummation techniques indispensable. As we shall see, the computation of avarage jet multiplicities indeed requires small-x resummation, as was already realized a long time ago [4]. In Ref. [4], it was shown that the singularities for x в€ј 0, which are encoded in large logarithms of the kind 1/x lnk (1/x), spoil perturbation theory, and also render integral observables in x ill-defined, disappear after resummation. Usually, resummation includes the singularities from all orders according to a certain logarithmic accuracy, for which it restores perturbation theory. Small-x resummation has recently been carried out for timelike splitting fuctions in the MS factorization scheme, which is generally preferable to other schemes, yielding fully analytic expressions. In a first step, the next-to-leadinglogarithmic (NLL) level of accuracy has been reached [5, 6]. In a second step, this has been pushed to the next-to-nextto-leading-logarithmic (NNLL), and partially even to the next-to-next-to-next-to-leading-logarithmic (N3 LL), level [7]. Thanks to these results, we were able in [1, 2] to analytically compute the NNLL contributions to the evolutions of the average gluon and quark jet multiplicities with normalization factors evaluated to next-to-leading (NLO) and в€љ approximately to next-to-next-to-next-to-order (N3 LO) in the О±s expansion. The previous literature contains a NLL result on the small-x resummation of timelike splitting fuctions obtained in a massive-gluon scheme. Unfortunately, this is unsuitable for the combination with available fixed-order corrections, which are routinely evaluated in the MS scheme. A general discussion of the scheme choice and dependence in this context may be found in Refs. [8]. The average gluon and quark jet multiplicities, which we denote as nh (Q2 ) g and nh (Q2 ) q , respectively, represent the average numbers of hadrons in a jet initiated by a gluon or a quark at scale Q. In the past, analytic predictions were obtained by solving the equations for the generating functionals in the modified leading-logarithmic approximation в€љ 3/2 (MLLA) in Ref. [9] through N3 LO in the expansion parameter О±s , i.e. through O(О±s ). However, the theoretical prediction for the ratio r(Q2 ) = nh (Q2 ) g / nh (Q2 ) q given in Ref. [9] is about 10% higher than the experimental data at the scale of the Z 0 boson, and the difference with the data becomes even larger at lower scales, although the perturbative series seems to converge very well. An alternative approach was proposed in Ref. [10], where a differential No-go for tree level R-symmetry breaking Feihu Liua, * , Muyang Liub, вЂ and Zheng Sunb, c вЂЎ arXiv:1412.0183v1 [hep-ph] 30 Nov 2014 a School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China b Center for Theoretical Physics, College of Physical Science and Technology, Sichuan University, Chengdu 610064, P. R. China c State Key Laboratory of Theoretical Physics and Kavli Institute for Theoretical Physics China (KITPC), Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China E-mail: * [email protected], вЂ [email protected], вЂЎ sun [email protected] Abstract We show that in gauge mediation models with tree level R-symmetry breaking where supersymmetry and Rsymmetries are broken by different fields, the gaugino mass either vanishes or finds contribution from loop level Rsymmetry breaking. Thus tree-level R-symmetry breaking is either no-go or redundant for phenomenology model building. 1 Introduction Supersymmetry (SUSY) [1] provides a natural solution to several unsolved problems in the Standard Model (SM), such as the gauge hierarchy problem, gauge coupling unification and dark matter candidates. Since supersymmetric particles (sparticles) have not been discovered yet, SUSY must be broken to give them heavy masses escaping the current experimental limit. To avoid light sparticles in the supersymmetric standard model (SSM), SUSY must be broken in a hidden sector, and then the SUSY breaking effects are mediated to the observable SSM sector by a messenger sector, giving sparticle mass spectrum and coupling constants which may be examined at the LHC or other future experiments. There are three competitive mediation mechanisms: gravity mediation, gauge mediation, and anomaly mediation. We are focusing on gauge mediation models [2, 3, 4] in this work. Following the discussion of the Nelson-Seiberg theorem [5, 6, 7], R-symmetries are required to build a generic SUSY breaking model. From phenomenology point of view, the R-symmetry needs to be broken spontaneously in order to allow for the gaugino mass. The R-symmetry is usually broken by the SUSY breaking pseudomodulus [8, 9, 10, 11] which gets a vacuum expectation value (VEV) at loop level through the Coleman-Weinberg potential [12], or through the inclusion of D-terms [13, 14]. There are also models with tree level R-symmetry breaking from tree level VEVs of fields other than the pseudomodulus [15, 16]. These models usually involve many fields with specific R-charges, and the gaugino mass is often generated from multiple VEVs of fields at both loop level and tree level in such complicated models [17]. A wide class of tree-level SUSY and R-symmetry breaking models with classically stable pseudomoduli spaces have been shown to give zero gaugino masses at one loop level [18, 19]. Nevertheness, it still remains unclear whether in principle the gaugino mass could be generated from tree level R-symmetry breaking. In gauge mediation models, the SUSY breaking fields are coupled to messengers which are charged under the SM gauge symmetry. SUSY breaking is mediated to the SSM sector through gauge interactions, and soft terms such as the gaugino mass emerge at low energy. For loop level R-symmetry breaking, the SUSY breaking pseudomodulus field X also breaks the R-symmetry at loop level. It has the VEV X = X + Оё2 FX . (1) The resulting gaugino mass is MgЛњ в€ј О± FX . 4ПЂ X (2) For a tree level R-symmetry breaking model, we have two fields which breaks SUSY and R-Symmetry respectively. They have VEVs X = Оё 2 FX , Y = Y . (3) 1 Large-Nc Regge spectroscopyв€— arXiv:1412.0124v1 [hep-ph] 29 Nov 2014 Wojciech Broniowski Institute of Physics, Jan Kochanowski University, 25-406 Kielce, Poland The H. NiewodniczaВґ nski Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Cracow, Poland Enrique Ruiz Arriola Departamento de FВґД±sica AtВґ omica, Molecular y Nuclear and Instituto Carlos I de FВґД±sica TeВґ orica y Computacional, Universidad de Granada, E-18071 Granada, Spain Pere Masjuan PRISMA Cluster of Excellence, Institut fВЁ ur Kernphysik, Johannes Gutenberg-UniverstВЁat, Mainz D-55099, Germany This talk, dedicated to Eef van Beveren on the occasion of his birthday, reviews some of our results concerning the hadron spectroscopy, Regge trajectories, and the large-Nc meson-dominance of hadronic form factors. PACS numbers: 12.38.Lg, 11.30, 12.38.-t The presentation is based on several of our recent papers [1вЂ“5] devoted to hadron spectroscopy involving the large-Nc arguments and Regge trajectories. We begin with a brief review of the old Hagedorn [6] idea, applied to the fundamental question of understanding the spectrum of QCD, as well as its applications to thermodynamic properties which find practical use in understanding the lattice data and modeling the relativistic heavy-ion collisions. The excitation function of QCD is presented in Fig. 1, where we plot the density of states (left panel) represented via the Breit-Wigner functions (for plotting purposes the stable states were attributed some finite width), as well as the cumulative number of states with mass below m. We include в€— Talk presented by WB at EEF70, Workshop on Unquenched Hadron Spectroscopy: Non-Perturbative Models and Methods of QCD vs. Experiment, Coimbra, Portugal, 1-5 September 2014 (1) An underlying symmetry determines all elements of CKM and PMNS up to a universal constant? 1 2 Hong-Wei Ke1в€— and Xue-Qian Li2вЂ School of Science, Tianjin University, Tianjin 300072, China School of Physics, Nankai University, Tianjin 300071, China arXiv:1412.0116v1 [hep-ph] 29 Nov 2014 Abstract Observing the CKM matrix elements written in different parametrization schemes, one can notice obvious relations among the sine-values of the CP phases in those schemes. Using the relations, we establish a few parametrization-independent equations, by which the matrix elements of the CKM matrix can be completely fixed up to a universal parameter. If it is true, we expect that there should exist a hidden symmetry in the nature which determines the relations. Moreover, it requires a universal parameter, naturally it would be the famous Jarlskog invariant which is also parametrization independent. Thus the four parameters (three mixing angles and one CP phase) of the CKM matrix are not free, but determined by the symmetry and the universal parameter. As we generalize the rules to the PMNS matrix for neutrino mixing, the CP phase of the lepton sector is predicted to be within a range of 0 в€ј 59в—¦ centered at 39в—¦ (in the Pa parametrization) which will be tested in the future experiments. PACS numbers: 12.15.Ff, 14.60.Pq, 12.15.Hh в€— вЂ [email protected] [email protected] 1 Complete One-Loop Corrections to e+ eв€’ в†’ П‡Лњ01 П‡Лњ01 h0 for Different Scenarios 1 S. M. Seif1 , T.A. Azim1 Faculty of Science, Physics Department, Cairo University, Giza, Egypt. (Dated: November 20, 2014) arXiv:1412.0109v1 [hep-ph] 29 Nov 2014 Abstract In the present work, the full one-loop corrections to the production of a light neutral minimal supersymmetric standard model Higgs boson (h0 ) with a pair of lightest neutralinos (П‡ Лњ01 ) in e+ eв€’ collisions within the Minimal Supersymmetric Standard Model (MSSM) are presented. The details of the renormalization scheme used are presented. Our results also include the QED corrections as well as the weak corrections. It is found that the contribution from the weak and QED corrections is significant and needs to be taken into account in the future linear collider experiments. Numerical results for two different SUSY scenarios вЂ”Higgsino and Gaugino scenariosвЂ” for e+ eв€’ в†’ П‡ Лњ01 П‡ Лњ01 h0 are given. PACS numbers: 1 Introduction fields. If supersymmetry is realized in nature, neutralinos should be found in the next generation of high enOne of the main goals of the Tevatron and the LHC ex- ergy experiments at Tevatron, LHC [6] and a future e+ eв€’ perimental programs was to detect a Higgs boson. On collider. Especially at a linear e+ eв€’ collider, it will be the 4th of July 2012, the CMS and the ATLAS exper- possible to perform measurements with high precision imental teams at the LHC, announced independently, [7, 8]. that they both discovered a previously unknown boson of mass between 125 and 127 GeV [1, 2, 3], whose beIn view of the experimental prospects, it is inevitable havior so far is "consistent with" a Higgs boson, and it is confirmed likely, on March 2013, to be a Higgs boson, to include higherвЂ“order terms in the calculation of the although yet it is unclear which model best supports the measured quantities in order to achieve theoretical preparticle or whether multiple Higgs bosons exist. This dictions matching the experimental accuracy. Former discovery has impact on the search for particles such as studies on char- ginoвЂ“pair production [9, 10, 11] and neutralino [4]. Supersymmetry (SUSY) is a novel space- scalarвЂ“quark decays [12] have revealed that the BornвЂ“ time symmetry between bosons and fermions. In realistic level predictions can be influenced significantly by oneвЂ“ models, SUSY is broken at the weak scale implying that loop radiative corrections. all Standard Model (SM) particles must have superpartners with masses in the range в€ј 100 вЂ“ 1000 GeV that will be accessible to colliders. In the Minimal Supersymmetric Standard Model (MSSM), there are as many as five Higgs mass states: two scalars, h 0 and H 0 , a pseudo scalar, A0 and a pair of charged bosons, H В± , which makes the experimental search more involved. The couplings of the Higgs bosons to the SUSY scalar fermions fЛњ to the charginos П‡ ЛњВ± and neutralinos П‡ Лњ0 depend on the softвЂ“SUSY breaking parameters and therefore carry information on the fundamental SUSY theory. Since the mass of neutralinos are among the precision observables with lots of information on the SUSYbreaking structure, the relations between the particle masses and the SUSY parameters are important theoretical quantities for precision calculations. In (MSSM) Лњ04 , which are the fermion [5], one has four neutralinos П‡ Лњ01 -П‡ mass eigenstates of the supersymmetric partners of the photon, the Z 0 boson, and the neutral Higgs bosons H01,2 . Their mass matrix depends on the parameters M1 , M2 , Вµ, and tan ОІ, where M1 and M2 the SU(2) and U(1) gauge mass parameter, tan ОІ = v1 /v2 with v1,2 the vacuum expectation values of the two neutral Higgs doublet In this paper, we use on-shell renormalization scheme in the loop calculations of the Higgs and neutralino sectors of the CP-conserving MSSM. The calculation was performed using the FeynArts and FormCalc computer packages. All the renormalization constants, required to determine the various counterterms for the Higgs, neutralino and other sectors, being implemented in the MSSM version of FeynArts [13] for completion at the one-loop level. The resulting amplitudes were algebraically simplified using FormCalc and then converted to a FORTRAN program. The LoopTools package was used to evaluate the one-loop scalar and tensor integrals [14]. The paper is arranged as follows: The analytical calculations of the Born cross section to the e+ eв€’ в†’ П‡ Лњ01 П‡ Лњ01 h0 process is given in section 2, where some numerical results are shown. The virtual, the electroweak, and the soft photonic corrections are studied in section 3. The numerical results are presented in section 4. Finally, the conclusions are given in section 5. 1 EPJ Web of Conferences will be set by the publisher DOI: will be set by the publisher c Owned by the authors, published by EDP Sciences, 2014 QCD prediction of jet structure in 2D trigger-associated momentum correlations and implications for multiple parton interactions Thomas A. Trainor1 arXiv:1412.0082v1 [hep-ph] 29 Nov 2014 1 CENPA 354290 University of Washington, Seattle, Washington, USA Abstract. The expression вЂњmultiple parton interactionsвЂќ (MPI) denotes a conjectured QCD mechanism representing contributions from secondary (semi)hard parton scattering to the transverse azimuth region (TR) of jet-triggered p-p collisions. MPI is an object of underlying-event (UE) studies that consider variation of TR nch or pt yields relative to a trigger condition (leading hadron or jet pt ). An alternative approach is 2D triggerassociated (TA) correlations on hadron transverse momentum pt or rapidity yt in which all hadrons from all p-p events are included. Based on a two-component (soft+hard) model (TCM) of TA correlations a jet-related TA hard component is isolated. Contributions to the hard component from the triggered dijet and from secondary dijets (MPI) can be distinguished, including their azimuth dependence relative to the trigger direction. Measured e+ -eв€’ and p- pВЇ fragmentation functions and a minimum-bias jet spectrum from 200 GeV p- pВЇ collisions are convoluted to predict the 2D hard component of TA correlations as a function of p-p collision multiplicity. The agreement between QCD predictions and TA correlation data is quantitative, confirming a dijet interpretation for the TCM hard component. The TA azimuth dependence is inconsistent with conventional UE assumptions. 1 Introduction In a high-energy physics (HEP) context dijet production has long been accepted as an important mechanism for hadron formation by parton fragmentation [1вЂ“3]. But in a heavy-ion context вЂњfreezeoutвЂќ from a flowing bulk medium is assumed to be the nearly-exclusive hadron production mechanism [4вЂ“6], and there are claims that bulkmedium collectivity may even play a role in p-p, p-A and d-A systems [7]. Previously-accepted contributions from minimum-bias (MB) dijets to high energy collisions are displaced by the claimed presence of strong collective motion (flows) in a thermalized bulk medium or quark-gluon plasma to explain spectrum and correlation structure. Such claims are based in part on the a priori assumption that all hadrons with transverse momentum pt < 2 GeV/c emerge from a thermalized bulk medium [8]. But that interval includes more than 90% of minimum-bias (MB) jet fragments, according to jet measurements and QCD predictions [9вЂ“12]. Analysis of spectra and correlations does appear to confirm a dominant role for dijet production at low pt in all collision systems [10, 12вЂ“17]. But we can further extend the QCD description of MB dijet manifestations at low pt , at least in p-p collisions. In previous studies a jet-related hard component was isolated from the pt spectrum of 200 GeV p-p collisions by means of its charge multiplicity nch dependence, leading to a two-component (soft+hard) spectrum model (TCM) [15]. The spectrum hard component for p-p spectra has been described quantitatively by a pQCD calculation [12] based on a MB jet (hard-scattered parton) spec- trum [18] and measured parton fragmentation functions (FFs) [9]. Those results establish that the spectrum and angular-correlation hard components in p-p collisions are jet related [10, 12], The present study extends that program with a method to predict 2D trigger-associated (TA) hadron correlations arising from dijets produced in high-energy p-p collisions based on measured FFs and a large-angle-scattered parton spectrum [19вЂ“21]. Identification of unique triggereddijet contributions to TA correlations in p-p collisions may then probe the phenomenon of multiple parton interactions (MPI) and test claims of bulk collectivity in p-A, d-A and heavy ion (A-A) collisions at the Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC). In this paper we define 2D trigger-associated (TA) correlations, derive a TA two-component model (TCM) and extract a TA hard component (HC) that may represent dijet fragments. We then derive a system to predict the TA HC via a measured MB jet spectrum and parton FFs. Comparisons with measured TA hard components serve to identify kinematic limits on dijet formation in p-p collisions. We isolate triggered dijets from secondary dijets (MPI) and test underlying-event (UE) assumptions. 2 p-p spectra and dijet production The TCM for 2D TA correlations is based on the TCM for 1D yt spectra from p-p collisions which we briefly summarize here. The p-p spectrum TCM is derived from the nch dependence of pt or transverse rapidity yt в‰Ў ln[(mt + pt )/mПЂ ] spectra. A вЂњsoftвЂќ component S (yt ) with fixed Femtoscopic Signature of Strong Radial Flow in High-multiplicity pp Collisions Yuji Hironoв€— and Edward Shuryak Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA (Dated: December 2, 2014) arXiv:1412.0063v1 [hep-ph] 29 Nov 2014 Hydrodynamic simulations are used to calculate the identical pion HBT radii, as a function of the pair momentum kT . This dependence is sensitive to the magnitude of the collective radial flow in the transverse plane, and thus comparison to ALICE data enables us to derive its magnitude. By using hydro solutions with variable initial parameters we conclude that in this case fireball explosions starts with a very small initial size, well below 1 fm. I. INTRODUCTION The so called Hanbury-Brown-Twiss (HBT) interferometry method originally came from radio astronomy [1] as intensity interferometry. The influence of Bose symmetrization of the wave function of the observed mesons in particle physics was first emphasized by Goldhaber et al. [2] and applied to proton-antiproton annihilation. Its use for the determination of the size/duration of the particle production processes had been proposed by Kopylov and Podgoretsky [3] and one of us [4]. Heavy-ion collisions, with its large multiplicities, turned the вЂњfemtoscopyвЂќ technique into a large industry. Early applications for RHIC heavy-ion collisions were in certain tension with the hydrodynamical models, but this issue was later resolved, see e.g. [5]. The development of the HBT method had made it possible to detect the magnitude and even deformations of the flow. Makhlin and Sinyukov [6] made the important observation that HBT radii are sensitive to collective flows of the matter. The radii decrease with the increase of the total transverse momentum kT = (p1T + p2T )/2 of the pair. A sketch shown in Fig.1 provides a qualitative explanation to this effect: the larger is kT , the brighter becomes a small (shaded) part of the fireball, which the radial flow is maximal and the its direction coincides with the direction of kT . This follows from maximization of the Dopplerblue-shifted thermal spectrum в€ј exp (в€’pВµ uВµ /Tf ). In this paper we will rely on this effect, as well as on ALICE HBT data, to deduce the magnitude of the flow in high multiplicity pp collisions. (Although we will not use those, let us also mention that the HBT method can also be used not only for determination of the radial flow, but for elliptic flow as well: see e.g. early STAR measurements [7]. Another development in the HBT field was a shift from two-particle to three-particle correlations [8], [9] available due to very high multiplicity of events as well as high luminosities of RHIC and LHC colliders.) With the advent of LHC it became possible to trigger on high multiplicity events, both in pp and pP b collisions: в€— Electronic address: [email protected] k1 kt v k2 FIG. 1: (Color online)Sketch of how the radial flow (arrows directed radially from the fireball center) influences the HBT radii. At small kT the whole fireball (the circle) is visible, but at larger kT one sees only the part co-moving in the same direction вЂ“ shown by shaded ellipse. the resulting sample revealed angular anisotropies v2 , v3 similar to anisotropic flows in heavy-ion (AA) collisions. At the moment the issue whether those can or cannot be described hydrodynamically is under debate. So far the discussion of the strength of the radial flow was based on the spectra of identified particles, see [12, 13]. In this paper we look at the radial flow from a different angle, using the measured HBT radii [10]. The HBT radii for pp collisions at LHC has been measured by the ALICE collaboration [10], as a function of multiplicity. Their magnitude has been compared to those coming from hydro modelling in Refs. [21, 22]. Our analysis of the HBT radii focus on the strength of the radial flow. We illustrate how the radii, and especially the ratio Ro /Rs , are indicative of the flow magnitude. While at minimally biased collisions and small multiplicities the observed HBT radii are basically independent of the pair transverse momentum kT , for high multiplicity the observed radii decrease with kT . So, the effect we are after appears only at the highest multiplicities вЂ“ the same ones which display hydro-like angular correlations and modifications of the particle spectra. The strongest decrease, as expected, is seen for the so called Ro radius, for which this reduction in the interval kT = 0.1 В· В· В· 0.7 GeV reaches about factor 4 in magnitude. The kT dependence of the HBT radii tells us about the strength of the flow. The reason these data are quite important is the following: the HBT radii at small kT Modified ПЂПЂ amplitude with Пѓ pole P. BydЛ‡zovskВґ ya , R. KamiВґ nskib , V. Nazarib Л‡ z/Prague 25068, Czech Republic Nuclear Physics Institute, ASCR, ReЛ‡ Institute of Nuclear Physics, Polish Academy of Sciences, KrakВґ ow 31-342, Poland a arXiv:1412.0013v1 [hep-ph] 28 Nov 2014 b A set of well known once subtracted dispersion relations with imposed crossing symmetry condiВЇ and О·О·) and P (ПЂПЂ, ПЃ2ПЂ, and ПЃПѓ) wave tion is used to modify unitary multichannel S (ПЂПЂ, K K, amplitudes mostly below 1 GeV. Before the modifications, these amplitudes significantly did not satisfy the crossing symmetry condition and did not describe the ПЂПЂ threshold region. Moreover, the pole of the S wave amplitude related with the f0 (500) meson (former f0 (600) or Пѓ) had much smaller imaginary part and bigger real one in comparison with those in the newest Particle Data Group Tables. Here, these amplitudes are supplemented by near threshold expansion polynomials and refitted to the experimental data in the effective two pion mass from the threshold to 1.8 GeV and to the dispersion relations up to 1.1 GeV. In result the self consistent, i.e. unitary and fulfilling the crossing symmetry condition, S and P wave amplitudes are formed and the Пѓ pole becomes much narrower and lighter. To eliminate doubts about the uniqueness of the so obtained sigma pole position short and purely mathematical proof of the uniqueness of the results is also presented. This analysis is addressed to a wide group of physicists and aims at providing a very effective and easy method of modification of, many presently used, ПЂПЂ amplitudes with a heavy and broad Пѓ meson without changing of their original mathematical structure. PACS numbers: 11.55.Fv,11.55.-m,11.80.Et,13.75.Lb I. INTRODUCTION New once-subtracted dispersion relations with the imposed crossing symmetry condition for the S-F wave ПЂПЂ amplitudes have recently been derived and presented in the Refs. [1, 2]. Further analysis of these equations in the Ref. [3] for the S and P waves (the so-called GKPY equations) led inter alia to very precise determination of the position of the pole related with the f0 (500) resonance (hereafter Пѓ). Importance and effectiveness of similar dispersion relations but with two subtractions, i.e. of the so-called Roy equations [4], were already presented on the example of the elimination of long standing up-down ambiguity in the ПЂПЂ S wave amplitude below 1 GeV [5, 6] and of determination of the quark condensate constants [7]. Quite recently the RoyвЂ™s equations were once again effectively exploited in searching for unique determination of the S and P wave ПЂПЂ scattering amplitudes [8вЂ“ 10]. Due to incorporation of two boundary conditions for these amplitudes, it was possible to find such analytical solution below 800 MeV in accordance with derived and proven theorem on the uniqueness of such solutions [11]. One of the byproduct of these analyses and those with GKPY equations [1, 3] was official and long-awaited significant modification of the position of the Пѓ pole in Particle Data Tables. For many years this state was appearing with mass and width noticeably larger than 500 MeV. For example in the Particle Data Tables in 2010 [12] the mass was in the range M = 400вЂ“1200 MeV and the full width О“ = 600вЂ“1000 MeV. Before year 1994 the Пѓ meson was even excluded from the Tables for about 20 years. Since 2012 its parameters are much better determined, i.e., M = 400вЂ“550 MeV and О“ = 400вЂ“700 MeV [13]. The reason for this many years of confusion and uncer- tainty about these parameters was that their determination was based mostly on fairly disparate and uncertain experimental results. Fortunately, well-grounded theoretical works based on dispersion relations with the imposed crossing symmetry condition, presented, e.g. in [1, 3, 8вЂ“10], provided very strong arguments to resolve the existing uncertainties. Despite of those big and widely accepted changes in parameters of the Пѓ meson many analyses can still use the old, i.e. significantly too wide and too massive, scalarisoscalar state below 1 GeV. The reason for this may be difficulties in changing parameters of some models or parametrizations to adapt them to the new requirements. Use of the correct and precise parametrizations of the ПЂПЂ amplitudes is, however, sometimes crucial especially when high precision of the final results is required. This can be particularly well seen, for example, in analyses of the ПЂПЂ final state interactions in the heavy mesons decays (e.g. B or D в†’ M ПЂПЂ where M is K or ПЂ) needed to determine parameters of a very small CP violation. Another kind of analyses which need correct and very precise ПЂПЂ amplitudes are those which pretend to describe spectrum of light mesons decaying into ПЂПЂ pairs in given partial waves and which strongly require verification of compliance with the crossing symmetry condition. ВЇ and О·О·) analOne of them is the multichannel (ПЂПЂ, K K, ysis of the ПЂПЂ scattering data presented in [14вЂ“16] which uses unitary amplitudes up to 1.8 GeV with proper analytical properties on the whole Riemann surface. However, in the construction of these amplitudes the crossing symmetry condition was not required what resulted in insufficiently precise description of the ПЂПЂ elastic region. Moreover, these amplitudes did not describe correctly the experimental data in the vicinity of the ПЂПЂ threshold. The aim of this work is to present a general method of On the microscopic nature of the photon strength function O. Achakovskiy and A. Avdeenkov Institute for Physics and Power Engineering, 249033 Obninsk, Russia S. Goriely Institut dвЂ™Astronomie et dвЂ™Astrophysique, ULB, CP 226, B-1050 Brussels, Belgium S. Kamerdzhievв€— Institute for Nuclear Power Engineering NRNU MEPHI, 249040 Obninsk, Russia arXiv:1412.0268v1 [nucl-th] 30 Nov 2014 S. Krewald Institut fВЁ ur Kernphysik, Forschungszentrum JВЁ ulich, D-52425 JВЁ ulich, Germany The pygmy dipole resonances and photon strength functions in stable and unstable Ni and Sn isotopes are calculated within the microscopic self-consistent version of the extended theory of finite fermi systems which includes phonon coupling effects. The Skyrme forces SLy4 is used. A pygmy dipole resonance in 72 Ni is predicted at the mean energy of 12.4 MeV exhausting 25% of the total energy-weighted sum rule. The microscopically obtained photon E1 strength functions are used to calculate nuclear reaction properties. For the first time, average radiative widths and radiative neutron capture cross sections have been calculated taking the phonon coupling into account as well as the uncertainties caused by various microscopic level density models. In all three quantities considered, the contribution of phonon coupling turned out to be significant and is found necessary to explain available experimental data. PACS numbers: 24.10.-i, 24.60.Dr, 24.30.Cz, 21.60.Jz Recently, Photon Strength Functions (PSF) for Snisotopes below the neutron separation threshold have been determined using the (3 He,3 HeвЂ™Оі) and (3 He,О±Оі) reactions [1] (and references therein). Commonly, one parameterizes the PSF phenomenologically using, for example, generalized Lorentzian models [2, 3]. The Sn data obtained in Ref.[1] show some extra strength near 8 MeV, which cannot be described by the traditional smooth phenomenological parameterizations. Such an additional strength is interpreted as a pygmy dipole resonance (PDR). Pygmy resonances exhausts typically about 1-2% of the Energy Weighted Sum Rule (EWSR) but, nevertheless, significantly increases the radiative neutron capture cross section and may affect the nucleosynthesis of neutron-rich nuclei by the r-process [4]. In neutron-rich nuclei, for example, 68 Ni [5] and, probably, 72 Ni, 74 Ni, the EWSR fraction is much larger. Note that for nuclei with small neutron separation energy, less than typically 3вЂ“4 MeV, the PDR properties are changed significantly [4], and therefore, phenomenological systematics obtained by fitting characteristics of stable nuclei cannot be applied. Given the importance of PSF both in astrophysics [4] and nuclear engineering [6], microscopic investigations are required, especially when extrapolations to exotic nuclei are needed. Mean-field approaches using effective nucleon interactions, such as the Hartree-Fock Bogoliubov method and the quasi-particle random-phase approximation (HFB+QRPA) [4], allow systematic self- в€— [email protected] consistent studies of isotope chains, and indeed have been included in modern nuclear reaction codes like EMPIRE [7] and TALYS [8]. Such an approach is of higher predictive power in comparison with phenomenological models. However, as we discuss below and as confirmed by recent experiments, the HFB+QRPA approach is necessary but not sufficient. To be exact, it should be complemented by the effect describing the interaction of single-particle degrees of freedom with the low-lying collective phonon degrees of freedom, known as the phonon coupling (PC). The experiments in the PDR energy region [1, 9, 10] have given additional information about the PDR and PSF structures. The PSF structures at 8-9 MeV in six Sn isotopes obtained by the Oslo method [1] could not be explained within both the standard phenomenological approach [1] and the microscopic HFB+QRPA approach [10]. In both cases, to explain the experiment, it was necessary to add вЂќby handвЂќ some additional strength of about 1вЂ“2% of the EWSR. The results [10] directly confirm the necessity to go beyond the HFB+QRPA method. In particular, the PC effects discussed in Refs.[11вЂ“13]1 may be at the origin of such an extra strength. In this work, we use the self-consistent version of the extended theory of finite fermi systems (ETFFS) [11] in 1 There are misprints in the English version of Ref.[13]: in all figure captions and in the discussions of the corresponding results there must stand QTBA instead of RQTBA, i.e. all calculations in Ref.[13] have been performed within the ETFFS(QTBA), or simply QTBA, (not RQTBA !). Activation cross sections of О±-particle induced nuclear reactions on hafnium and deuteron induced nuclear reaction on tantalum: production of 178 W/178m Ta generator F. TВґarkВґanyia , S. TakВґacsa , F. DitrВґoia,в€—, A. Hermanneb , A.V. Ignatyukd , M.S. Uddinc arXiv:1412.0411v1 [nucl-ex] 1 Dec 2014 a Institute for Nuclear Research, Hungarian Academy of Sciences (ATOMKI), Debrecen, Hungary b Cyclotron Laboratory, Vrije Universiteit Brussel (VUB), Brussels, Belgium c Cyclotron Radioisotope Center (CYRIC), Tohoku University, Sendai, Japan d Institute of Physics and Power Engineering (IPPE), Obninsk, Russia Abstract In the frame of a systematic study of charged particle production routes of medically relevant radionuclei, the excitation function for indirect production of 178m Ta through nat Hf(О±,xn)178в€’178m Ta nuclear reaction was measured for the first time up to 40 MeV. In parallel, the side reactions nat Hf(О±,x)179,177,176,175 W, 183,182,178g,177,176,175 Ta, 179m,177m,175 Hf were also assessed. Stacked foil irradiation technique and Оі-ray spectrometry were used. New experimental cross section data for the nat Ta(d,xn)178 W reaction are also reported up to 40 MeV. The measured excitation functions are compared with the results of the ALICE-IPPE, and EMPIRE nuclear reaction model codes and with the TALYS 1.4 based data in the TENDL-2013 library. The thick target yields were deduced and compared with yields of other charged particle ((p,4n), (d,5n) and (3 He,x)) production routes for 178 W. Keywords: hafnium and tantalum target, О±-irradiation, deuteron irradiation, hafnium, tantalum and tungsten radioisotopes, physical yield, 178 W production 1. Introduction The short-lived (9.3 min) metastable state of the 178 Ta a radioisotope can be used both for diagnostic (PET studies, total ОІ+ decay: 1.24%) as well as for therapeutic purposes (KО±1 + KО± 2 60%) (Lacy et al., 2001; Layne and Lacy, 1990; Nichols, 2013; Wilson et al., 1987). It can be produced from long-lived (21.7 d) 178 W via a 178 W/178 Ta generator. The used production routes include proton and deuteron induced reactions on tantalum and alpha and 3 He particle induced reactions on hafnium. In the frame of a coordinated research project of the IAEA the evaluation of cross sections of production routes of several medical radioisotopes, including the so called generator isotopes, is in progress (Nichols, 2013). The production routes for a 178 W/178 Ta generator were previously compiled (not evaluated) in another IAEA project dealing with the physical characteristics and production methods of cyclotron produced radionuclides (Haji-Saeid et al., 2009). The compilation of the available experimental cross section results showed no в€— Corresponding satisfactory data set. No cross section data are available for the nat Hf(О±,xn)178 W reaction. Among the possible production routes we also measured cross sections (up to 70 MeV) and made theoretical calculation for the nat Ta(p,x)178 W reaction (Uddin et al., 2004). We also investigated activation cross sections for deuteron induced reactions on Ta up to 40 MeV, but cross section data for 178 W production were not reported (Hermanne et al., 2009). In this work we experimentally investigate the excitation function of the nat Hf(О±,xn)178 W reaction and the accompanying side reactions, and by re-evaluating the spectra obtained in our earlier nat Ta(d,x) experiment we report cross sections of the nat Ta(d,x)178 W reaction. To show the capability of different nuclear reaction codes, the measured excitation functions are compared with the results obtained with ALICE-IPPE, EMPIRE and TALYS 1.4 (data from the TENDL-2013 online library) nuclear reaction codes. The thick target yields were deduced and also compared with yields of other charged particle production routes for 178 W. The Ta is nearly monoisotopic, consists of 99.988% 181 Ta and only 0.012 % 180 Ta, therefore under the present un- author: [email protected] Preprint submitted to Applied Radiation and Isotopes December 2, 2014 arXiv:1412.0274v1 [nucl-ex] 30 Nov 2014 Measurements of ep в†’ e ПЂ + n at 1.6 < W < 2.0 GeV and extraction of nucleon resonance electrocouplings at CLAS K. Park,35, 28 I.G. Aznauryan,35, 41 V.D. Burkert,35 K.P. Adhikari,28 M.J. Amaryan,28 S. Anefalos Pereira,16 H. Avakian,35 M. Battaglieri,17 R. Badui,10 I. Bedlinskiy,21 A.S. Biselli,9, 29 J. Bono,10 W.J. Briscoe,13 W.K. Brooks,36, 35 D.S. Carman,35 A. Celentano,17 S. Chandavar,27 G. Charles,20 L. Colaneri,18 P.L. Cole,14, 35 M. Contalbrigo,15 O. Cortes,14 V. Crede,11 A. DвЂ™Angelo,18, 31 N. Dashyan,41 R. De Vita,17 E. De Sanctis,16 A. Deur,35 C. Djalali,33 D. Doughty,7, 35 R. Dupre,20 H. Egiyan,35 A. El Alaoui,36 L. Elouadrhiri,35 L. El Fassi,28, в€— P. Eugenio,11 G. Fedotov,33, 32 S. Fegan,17 R. Fersch,40, вЂ A. Filippi,19 J.A. Fleming,37 B. Garillon,20 M. GarВёcon,6 N. Gevorgyan,41 G.P. Gilfoyle,30 K.L. Giovanetti,22 F.X. Girod,35 H.S. Joo,20 J.T. Goetz,27 E. Golovatch,32 R.W. Gothe,33 K.A. Griffioen,40 B. Guegan,20 M. Guidal,20 L. Guo,10, 35 H. Hakobyan,36, 41 C. Hanretty,39, вЂЎ M. Hattawy,20 K. Hicks,27 M. Holtrop,25 S.M. Hughes,37 C.E. Hyde,28 Y. Ilieva,33 D.G. Ireland,38 B.S. Ishkhanov,32 E.L. Isupov,32 D. Jenkins,43 H. Jiang,33 H.S. Jo,20 K. Joo,8 S. Joosten,34 D. Keller,39 M. Khandaker,14, 26 A. Kim,23, В§ W. Kim,23 A. Klein,28 F.J. Klein,5 V. Kubarovsky,35, 29 S.E. Kuhn,28 S.V. Kuleshov,36, 21 P. Lenisa,15 K. Livingston,38 H.Y. Lu,33 I .J .D. MacGregor,38 N. Markov,8 D. Martinez,14 B. McKinnon,38 V. Mokeev,35, 32 R.A. Montgomery,16, В¶ H. Moutarde,6 C. Munoz Camacho,20 P. Nadel-Turonski,35 S. Niccolai,20, 13 G. Niculescu,22, 27 I. Niculescu,22 M. Osipenko,17 A.I. Ostrovidov,11 M. Paolone,34 E. Pasyuk,35 P. Peng,39 W. Phelps,10 J.J. Phillips,38 S. Pisano,16 O. Pogorelko,21 J.W. Price,2 S. Procureur,6 Y. Prok,28, 39 D. Protopopescu,38 A.J.R. Puckett,8 B.A. Raue,10, 35 M. Ripani,17 A. Rizzo,18 G. Rosner,38 P. Rossi,16, 35 P. Roy,11 F. SabatiВґe,6 C. Salgado,26 D. Schott,13 R.A. Schumacher,4 E. Seder,8 Y.G. Sharabian,35 A. Simonyan,41 Iu. Skorodumina,33, 44 E.S. Smith,35 G.D. Smith,37 N. Sparveris,34 P. Stoler,29 I.I. Strakovsky,13 S. Strauch,33 V. Sytnik,36 M. Taiuti,12, в€—в€— W. Tang,27 C.E. Taylor,14 Ye Tian,33 A. Trivedi,33 M. Ungaro,35, 29 H. Voskanyan,41 E. Voutier,24 N.K. Walford,5 D.P. Watts,37 X. Wei,35 L.B. Weinstein,28 M.H. Wood,3, 33 N. Zachariou,33 L. Zana,37 J. Zhang,35 Z.W. Zhao,39 and I. Zonta18 (The CLAS Collaboration) 1 Arizona State University, Tempe, Arizona 85287-1504, USA California State University, Dominguez Hills, Carson, California 90747, USA 3 Canisius College, Buffalo, New York, USA 4 Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA 5 Catholic University of America, Washington, D.C. 20064, USA 6 CEA, Centre de Saclay, Irfu/Service de Physique NuclВґeaire, 91191 Gif-sur-Yvette, France 7 Christopher Newport University, Newport News, Virginia 23606, USA 8 University of Connecticut, Storrs, Connecticut 06269, USA 9 Fairfield University, Fairfield Connecticut 06824, USA 10 Florida International University, Miami, Florida 33199, USA 11 Florida State University, Tallahassee, Florida 32306, USA 12 Universit` a di Genova, 16146 Genova, Italy 13 The George Washington University, Washington, DC 20052, USA 14 Idaho State University, Pocatello, Idaho 83209, USA 15 INFN, Sezione di Ferrara, 44100 Ferrara, Italy 16 INFN, Laboratori Nazionali di Frascati, 00044 Frascati, Italy 17 INFN, Sezione di Genova, 16146 Genova, Italy 18 INFN, Sezione di Roma Tor Vergata, 00133 Rome, Italy 19 INFN, sez. di Torino, 10125 Torino, Italy 20 Institut de Physique NuclВґeaire ORSAY, Orsay, France 21 Institute of Theoretical and Experimental Physics, Moscow, 117259, Russia 22 James Madison University, Harrisonburg, Virginia 22807, USA 23 Kyungpook National University, Daegu 702-701, Republic of Korea 24 LPSC, UniversitВґe Grenoble-Alpes, CNRS/IN2P3, Grenoble, France 25 University of New Hampshire, Durham, New Hampshire 03824-3568, USA 26 Norfolk State University, Norfolk, Virginia 23504, USA 27 Ohio University, Athens, Ohio 45701, USA 28 Old Dominion University, Norfolk, Virginia 23529, USA 29 Rensselaer Polytechnic Institute, Troy, New York 12180-3590, USA 30 University of Richmond, Richmond, Virginia 23173, USA 31 UniversitaвЂ™ di Roma Tor Vergata, 00133 Rome Italy 32 Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119234 Moscow, Russia 33 University of South Carolina, Columbia, South Carolina 29208, USA 34 Temple University, Philadelphia, PA 19122, USA 35 Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA 2 2 36 Universidad TВґecnica Federico Santa MarВґД±a, Casilla 110-V ValparaВґД±so, Chile 37 Edinburgh University, Edinburgh EH9 3JZ, United Kingdom 38 University of Glasgow, Glasgow G12 8QQ, United Kingdom 39 University of Virginia, Charlottesville, Virginia 22901, USA 40 College of William and Mary, Williamsburg, Virginia 23187-8795, USA 41 Yerevan Physics Institute, 375036 Yerevan, Armenia 42 Argonne National Laboratory, Argonne, Illinois 60439, USA 43 Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0435, USA 44 M.V.Lomonosov Moscow State University,Leninskie Gory, Moscow 119991, Russia Differential cross sections of the exclusive process ep в†’ e ПЂ + n were measured with good precision in the range of the photon virtuality Q2 = 1.8 в€’ 4.5 GeV2 , and the invariant mass range of the + ПЂ n final state W = 1.6 в€’ 2.0 GeV using the CEBAF Large Acceptance Spectrometer. Data were collected with nearly complete coverage in the azimuthal and polar angles of the nПЂ + center-of-mass system. More than 37,000 cross section points were measured. The contributions of the isospin I = 21 в€’ + + resonances N (1675) 52 , N (1680) 52 and N (1710) 21 were extracted at different values of Q2 using a single-channel, energy-dependent resonance amplitude analysis. Two different approaches, the unitary isobar model and the fixed-t dispersion relations, were employed in the analysis. We observe в€’ significant strength of the N (1675) 25 in the A1/2 amplitude, which is in strong disagreement with + quark models that predict both transverse amplitudes to be strongly suppressed. For the N (1680) 52 we observe a slow changeover from the dominance of the A3/2 amplitude at the real photon point (Q2 = 0) to a Q2 where A1/2 begins to dominate. The scalar amplitude S1/2 drops rapidly with Q2 + consistent with quark model prediction. For the N (1710) 12 resonance our analysis shows significant strength for the A1/2 amplitude at Q2 < 2.5 GeV2 . PACS numbers: 13.40.Gp, 13.60.Le, 14.20.Gk, 25.30.Rw I. INTRODUCTION The study of the excited states of the nucleon is an important step in the development of a fundamental understanding of the strong interaction [1]. While the existing data on the low-lying resonances are consistent with the well-studied SU (6) вЉ— O(3) constituent quark model classification, many open questions remain. On a fundamental level there exists only a very limited understanding of the relationship between Quantum Chromo-Dynamics (QCD), the field theory of the strong interaction, and the constituent quark model (CQM) or alternative hadron models, however recent developments in Lattice QCD, most notably the predictions of the spectrum of N в€— and в€†в€— states, have shown [2] that the same symmetry of SU (6) вЉ— O(3) is likely at work here as is underlying the spectrum in the CQM. Experimentally, we still do not have sufficiently complete data that can be used to uncover unambiguously the structure of the nucleon and its excited states in the в€— Current address:Mississippi State University, 125 Hilbun Hall, Miss State, Mississippi 39762, USA вЂ Current address:Christopher Newport University, Newport News, Virginia 23606, USA вЂЎ Current address:Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA В§ Current address:University of Connecticut, Storrs, Connecticut 06269, USA В¶ Current address:University of Glasgow, Glasgow G12 8QQ, United Kingdom в€—в€— Current address:INFN, Sezione di Genova, 16146 Genova, Italy entire resonance mass range. While this remains an important long term goal, very significant advances have been made during the past decade that have enabled the precise determination of resonance electrocouplings for a set of lower mass states and in a wide space-time range. Precise data have become available in recent years [3вЂ“10] to study the transition from the nucleon ground state to the в€†(1232), in ПЂ 0 electroproduction on the proton with wide angular coverage and in a wide range of fourmomentum transfer Q2 . This has allowed for the determination of the magnetic dipole transition form factor and the electric and scalar quadrupole transition, covering a range of 0 в‰¤ Q2 в‰¤ 7 GeV2 (we set c = 1). This information, combined with precise cross section and polarization data for the processes ep в†’ e ПЂ 0 p [3, 4, 11], ep в†’ e ПЂ + n [12вЂ“14] and ep в†’ e О·p [15вЂ“17] in the second nucleon resonance region near W = 1.35 в€’ 1.6 GeV allowed for precise measurements of electrocouplings of + the вЂќRoperвЂќ resonance N (1440) 12 [18], which in the CQM is the first radial excitation of the nucleon. These results solved a longstanding question regarding the nature of this state. Precise results have also been obtained в€’ в€’ for the transition to the N (1535) 12 and the N (1520) 32 states. Following these breakthroughs, the process ep в†’ + в€’ 2 epПЂ ПЂ was measured in the lower Q and low mass range [19], and a reaction model was developed [20] that enabled extraction of the electrocoupling amplitudes for + в€’ the resonances N (1440) 12 and N (1520) 32 [21] from this channel. The two-pion results were consistent with the results from the single pion analysis, and thus validated the analysis approach for this more complex reaction channel. This is a highly non-trivial result as the non- Status of some P-wave baryon resonances and importance of inelastic channels Volker D. Burkert,1 Hiroyuki Kamano,2 Eberhard Klempt,3 Deborah RВЁonchen,4 Andrey 6 Л‡ V. Sarantsev,3 Toru Sato,5 Alfred Svarc, Lothar Tiator,7 and Ron L. Workman8 1 arXiv:1412.0241v1 [nucl-ex] 30 Nov 2014 2 Jefferson Lab, 12000 Jefferson Avenue, Newport News, Virginia 23606, USA Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047, Japan 3 Helmholtz-Institut fВЁ ur Strahlen- und Kernphysik, UniversitВЁ at Bonn, Germany Petersburg Nuclear Physics Institute, Gatchina, Russia 4 Helmholtz-Institut fВЁ ur Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, UniversitВЁ at Bonn, NuГџallee 14-16, 53115 Bonn, Germany 5 Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan 6 Rudjer BoЛ‡skoviВґc Institute, BijeniЛ‡cka cesta 54, P.O. Box 180, 10002 Zagreb, Croatia 7 Institut fВЁ ur Kernphysik, UniversitВЁ at Mainz, D-55099 Mainz, Germany 8 Data Analysis Center at the Institute for Nuclear Studies, Department of Physics, The George Washington University, Washington, D.C. 20052 (Dated: December 2, 2014) Abstract We analyze the current status of three P-wave baryon states N (1710)1/2+ , N (1900)3/2+ , and в€†(1600)3/2+ as given in the Review of Particles Physics (RPP). Since the evidence for a particleвЂ™s existence is linked to its RPP вЂќstarвЂќ rating, we discuss its subjective present definition. We also present the accumulating evidence supporting these states and give our new вЂќstarвЂќ rating recommendations. PACS numbers: I. INTRODUCTION In recent years, the field of light-flavor baryon spectroscopy has seen a tremendous increase in experimental activity. High-precision cross section and polarization data are now available, from numerous single and double-meson photoproduction experiments, and these have become the broadest source of information on new baryon states. The bi-annually released Review of Particle Physics (RPP) is the primary source of information relied upon by researchers in the field of baryon physics. The RPP tabulates baryon resonance candidates together with their properties and provides an assessment of their reliability, both overall and separately from pion and photon induced reactions. We have therefore focused our discussion on the ratings provided by this source. The RPP assigns a star-rating from one to four stars for baryon resonance candidates. The one and two-star states are rated from poor to fair, whereas the three and four-star states have a rating from likely to certain. These higher-rated states appear in the Baryon Summary Tables without reference to any star rating. The more detailed Particle Listings tabulate overall and reactionspecific star ratings for each resonance. The three P+ wave baryon states, N (1710)(1/2)+ , N (1900)3/2 , and + в€†(1600)3/2 , are presently given an overall three-star rating, which prompts the question: Have these states been confirmed or are they merely вЂ™likelyвЂ™ to exist? It should be mentioned that neither the definition of a star rating nor the ratings themselves have remained static since these states were identified. Many states were downgraded, with some three-star rated states being eliminated, between the 1982 [1] and 1984 [2] editions of the RPP. This upheaval was prompted by disagreements between newer measurements and the older existing data and analyses [3]. In particular, the N (1710)(1/2)+ was demoted from a 4-star to a 3-star status, while the в€†(1600)(3/2)+ dropped from a 3-star to a 2-star status. As a result, the в€†(1600)(3/2)+ was dropped from the Baryon Summary Table. Its status was later raised back to three stars [4], having been seen in subsequent analyses [5, 6] of the Virginia Tech and Kent State groups, the uncertainty in its properties preventing a 4-star rating. Many topics related to the extraction of resonance properties, from the newly accumulated high-precision data, were subjects of discussions at the 2014 ECT* Workshop вЂќExciting Baryons: Design and Analysis of Complete Experiments for Meson PhotoproductionвЂќ [7]. The presence of many experts in the field enabled a meeting where the status of prominent 3-star resonances Momentum sharing in imbalanced Fermi systems Authors: O. Hen40*, M. Sargsian10, L.B. Weinstein27, E. Piasetzky40, H. Hakobyan34,39, D. W. Higinbotham33, M. Braverman40, W.K. Brooks34, S. Gilad41, K. P. Adhikari27, J. Arrington1, G. Asryan39, H. Avakian33, J. Ball7, N. A. Baltzell1, M. Battaglieri17, A. Beck40,43, S. May-Tal Beck40,43, I. Bedlinskiy20, W. Bertozzi41, A. Biselli42, V. D. Burkert33, T. Cao32, D. S. Carman33, A. Celentano17, S. Chandavar26, L. Colaneri18, P. L. Cole14,6,33, V. Crede11, A. DвЂ™Angelo18,30, R. De Vita17, A. Deur33, C. Djalali32, D. Doughty8,33, M. Dugger2, R. Dupre19, H. Egiyan33, A. El Alaoui1, L. El Fassi27, L. Elouadrhiri33, G. Fedotov32,31, S. Fegan17, T. Forest14, B. Garillon19, M. Garcon7, N. Gevorgyan39, Y. Ghandilyan39, G. P. Gilfoyle29, F. X. Girod33, J. T. Goetz26, R. W. Gothe32, K. A. Griffioen38, M. Guidal19, L. Guo10,33, K. Hafidi1, C. Hanretty37, M. Hattawy19, K. Hicks26, M. Holtrop24, C. E. Hyde27, Y. Ilieva32,13, D. G. Ireland36, B.I. Ishkanov31, E. L. Isupov31, H. Jiang32, H. S. Jo19, K. Joo9, D. Keller37, M. Khandaker14,25, A. Kim22, W. Kim22, F. J. Klein6, S. Koirala27, I. Korover40, S. E. Kuhn27, V. Kubarovsky33, P. Lenisa15, W. I. Levine5, K. Livingston36, M. Lowry33, H. Y. Lu32, I. J. D. MacGregor36, N. Markov9, M. Mayer27, B. McKinnon36, T. Mineeva9, V. Mokeev19,33, A. Movsisyan15, C. Munoz Camacho19, B. Mustapha1, P. Nadel-Turonski33, S. Niccolai19, G. Niculescu21, I. Niculescu21, M. Osipenko17, L. L. Pappalardo15, R. Paremuzyan39, K. Park33,22, E. Pasyuk33, W. Phelps10, S. Pisano16, O. Pogorelko20, J. W. Price3, S. Procureur7, Y. Prok27,37, D. Protopopescu36, A. J. R. Puckett9, D. Rimal10, M. Ripani17, B. G. Ritchie2, A. Rizzo18, G. Rosner36, P. Rossi33, P. Roy11, F. Sabati МЃe7, D. Schott13, R. A. Schumacher5, Y. G. Sharabian33, G. D. Smith35, R. Shneor40, D. Sokhan36, S. S. Stepanyan22, S. Stepanyan33, P. Stoler28, S. Strauch32,13, V. Sytnik34, M. Taiuti12, S. Tkachenko37, M. Ungaro33, A. V. Vlassov20, E. Voutier23, N. K. Walford6, X. Wei33, M. H. Wood4,32, S. A. Wood33, N. Zachariou32, L. Zana35,24, Z. W. Zhao37, X. Zheng37, and I. Zonta18. (Jefferson Lab CLAS Collaboration) Affiliations: 1 Argonne National Laboratory, Argonne, Illinois 60439. 2 Arizona State University, Tempe, Arizona 85287-1504. 3 California State University, Dominguez Hills, Carson, CA 90747. 4 Canisius College, Buffalo, NY. 5 Carnegie Mellon University, Pittsburgh, Pennsylvania 15213. 6 Catholic University of America, Washington, D.C. 20064. 7 CEA, Centre de Saclay, Irfu/Service de Physique Nucl МЃeaire, 91191 Gif-sur-Yvette, France. 8 Christopher Newport University, Newport News, Virginia 23606. 9 University of Connecticut, Storrs, Connecticut 06269. 10 Florida International University, Miami, Florida 33199. 11 Florida State University, Tallahassee, Florida 32306. 12 Universita` di Genova, 16146 Genova, Italy. Abstract: The atomic nucleus is composed of two different kinds of fermions, protons and neutrons. If the protons and neutrons did not interact, the Pauli exclusion principle would force the majority fermions (usually neutrons) to have a higher average momentum. Our high-energy electron scattering measurements using 12C, 27Al, 56Fe and 208Pb targets show that, even in heavy neutron-rich nuclei, short-range interactions between the fermions form correlated highmomentum neutron-proton pairs. Thus, in neutron-rich nuclei, protons have a greater probability than neutrons to have momentum greater than the Fermi momentum. This finding has implications ranging from nuclear few body systems to neutron stars and may also be observable experimentally in two-spin state, ultra-cold atomic gas systems. Main Text: Many-body systems composed of interacting fermions are common in nature, ranging from high-temperature superconductors and Fermi liquids to atomic nuclei, quark matter and neutron-stars. Particularly intriguing are systems that include a short-range interaction that is strong between unlike fermions and weak between fermions of the same kind. Recent theoretical advances show that even though the underlying interaction can be very different, these systems share several universal features (1-4). In all these systems, this interaction creates short-range correlated (SRC) pairs of unlike fermions with a large relative momentum (krel > kF) and a small center of mass (CM) momentum (ktot < kF), where kF is the Fermi momentum of the system. This pushes fermions from low momenta (k < kF where k is the fermion momentum) to high momenta (k > kF), creating a вЂњhigh momentum tailвЂќ. SRC pairs in atomic nuclei have been studied using many different reactions, including pickup, stripping and electron and proton scattering. The results of these studies highlighted the importance of correlations in nuclei, which lead to a high momentum tail and decreased occupancy of low-lying nuclear states (5-13). Recent experimental studies of balanced (symmetric) interacting Fermi systems, with an equal number of fermions of the two kinds, confirmed these predictions of a high momentum tail populated almost exclusively by pairs of unlike fermions (8-11,14-16). These experiments were done using very different Fermi systems: protons and neutrons in atomic nuclei and two-spin state ultra-cold atomic gasses. These systems span more than 15 orders of magnitude in Fermi energy from 106 to 10-9 eV and exhibit different short-range interactions (predominantly a strong tensor interaction in the nuclear systems (8,9,17,18), and a tunable Feshbach resonance in the

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