Mu2e
CSN1 Presentation
December 3, 2012
Ron Ray
Mu2e Project Manager
Overview
•
•
•
•
•
•
Introduction
Mu2e Sensitivity to New Physics
Experimental Method
Mu2e Project Status
INFN Contributions to Mu2e
Summary
Dec. 3, 2012
R. Ray - CSN1 Presentation
2
Introduction
• Mu2e experiment is a search for Charged Lepton Flavor
Violation (CLFV) via the coherent conversion of m-N  e-N
• Mu2e will use current proton source at Fermilab to achieve
world’s best sensitivity
• Target sensitivity has great discovery potential
 Goal: <0.5 events background
 Goal: Single-event-sensitivity of 2 x 10-17
(this yields Discovery Sensitivity for all rates > few 10-16)
• Factor of 104 improvement over world’s previous best
results
 W.Bertl et al. (Sindrum II), Eur Phys J C47 (2006) 337
 C. Dohmen et al. (Sindrum II), Phys Lett B317 (1993) 631
Dec. 3, 2012
R. Ray - CSN1 Presentation
3
Introduction
• Discovery sensitivity over a very broad range of New
Physics Models
 SuperSymmetry, Little Higgs, Leptoquarks, Extended Technicolor,
Extra Dimensions, …
 A null result at the target sensitivity will severely constrain new
physics models.
• Complementary sensitivity to rest of the world HEP
program
 MEG, LHC, n mixing, B-factory
Dec. 3, 2012
R. Ray - CSN1 Presentation
4
Some CLFV Processes
Process
Current Limit
--m
BR < 6.5 E-8
--m
BR < 6.8 E-8
--mmm
BR < 3.2 E-8
--eee
BR < 3.6 E-8
KL --> em
BR < 4.7 E-12
K+ --> e-m
BR < 1.3 E-11
B0 --> em
BR < 7.8 E-8
B+ --> K+em
BR < 9.1 E-8
m--e+
BR < 2.4 E-12
m--e+e+e-
BR < 1.0 E-12
mN --> eN
Rme < 4.3 E-12
Next Generation exp
10-9 - 10-10 (Future B factories)
10-13 (MEG)
10-16 (Mu2e, COMET)
• Relative sensitivities model dependent
• Measure several to pin-down details of new physics
Dec. 3, 2012
R. Ray - CSN1 Presentation
5
Contact Terms
Loops
New Physics Contributions to mNeN
Supersymmetry
Compositeness
Heavy Neutrinos
Leptoquarks
Two Higgs Doublets
New Heavy Bosons /
Anomalous Couplings
mNeN sensitive to wide array of New Physics models
Dec. 3, 2012
R. Ray - CSN1 Presentation
6
• Mu2e mass reach ~104 TeV
• Target Mu2e sensitivity best in all
scenarios.
• ~×2 beyond MEG in loop-dominated
physics.
Higher mass scale
Sensitivity
A. de Gouvea
Project X Workshop
Golden Book
Dec. 3, 2012
R. Ray - CSN1 Presentation
7
Mu2e Sensitivity
hep-ph/0702136v3
Rate mNeN
Colors denote different model scenarios
Current Limit
BR(me)
• Mu2e will cover the entire space
• Most likely result would be near the existing experimental limit – large signal!
Dec. 3, 2012
R. Ray - CSN1 Presentation
8
Mu2e Sensitivity
Sensitivity to Warped Compact Extra Dimensions
Scan of Randall-Sundrum Parameter space
hep-ph/0606021v2
• Mu2e, MEG will each cover entire space
• Definitive test of R-S geometric origin of lepton hierarchy at the TeV scale.
Dec. 3, 2012
R. Ray - CSN1 Presentation
9
Mu2e Sensitivity
BR(m) / 10-7
PMNS
CKM
BR(me) / 10-11
Scan of SUSY – GUT parameters
M1/2 (GeV/c2)
• me, m will begin to probe this space
Dec. 3, 2012
R. Ray - CSN1 Presentation
10
Mu2e Sensitivity
Scan of SUSY – GUT parameters
Rate mN  eN / 10-12
PMNS
CKM
Sindrum II
hep-ph/0605139v2
Mu2e
M1/2 (GeV/c2)
• Mu2e will cover (almost) entire space
Dec. 3, 2012
R. Ray - CSN1 Presentation
11
SUSY
• These are SUSY benchmark points for which LHC has
discovery sensitivity
• Some of these will be observable by MEG/B Factories
• All of these will be observable by Mu2e
Dec. 3, 2012
R. Ray - CSN1 Presentation
12
Mu2e, MEG and the LHC
Mu2e is important regardless of what happens with MEG or
the LHC
• If MEG sees a signal Mu2e also has sensitivity. Besides a
confirmation of CLFV, combination of mN  eN and BR(m e) is a
powerful discriminator between new physics models.
• If MEG sees no signal, Mu2e has sensitivity to new physics that MEG
does not, so observation still possible.
• If LHC discovers new physics, Mu2e and Mu2e/MEG can provide
insight into its interpretation.
• If LHC does not discover new physics, Mu2e has a reach of ~104
TeV, so discovery still possible.
Mu2e is a potential discovery experiment that is relevant in
all possible scenarios.
Dec. 3, 2012
R. Ray - CSN1 Presentation
13
History/Future of CLFV
MEG
MEG upgrade
Mu2e, COMET
PSI, MUSIC
Project X, PRIME
Dec. 3, 2012
R. Ray - CSN1 Presentation
14
Experimental Method
• Generate a beam of low momentum muons
(m-
• Stop the muons in a target
e- m-
 Mu2e plans to use aluminum
 Sensitivity goal requires ~1018 stopped muons
X
Coherent recoil of nucleus
• The stopped muons are trapped in orbit around
the nucleus
 In orbit around aluminum: mAl = 864 ns
 Large mN important for discriminating background
• Look for events consistent with mN  eN
 Monoenergetic 105 MeV eDec. 3, 2012
R. Ray - CSN1 Presentation
15
Mu2e Apparatus
Production Solenoid
• Production target
• Graded field
• Delivers ~ 0.0016 stopped
m- per incident proton
• 1010 Hz of stopped muons
Detector Solenoid
• Muon stopping target
• Tracker
• Calorimeter
Transport Solenoid
• Warmrange
bore evacuated to
• Collimation system selects muon charge and momentum
10-4 Torr
• Pbar window in middle of central collimator
Cosmic Ray Veto not shown
Production Solenoid
Proton Beam
Detector Solenoid
2.5 T
4.6 T
Transport Solenoid
1T
1T
2T
Production Target
Dec. 3, 2012
Tracker
R. Ray - CSN1 Presentation
Calorimeter
16
Beam Structure
Prompt background:
Processes where the detected
background electron is nearly
coincident in time with the
arrival of a beam particle at
the muon stopping target.
Radiative Pion Capture
Target foils
Pulsed beam combined with
extinction of beam between
pulses and delayed search
window reduces prompt
backgrounds like Radiative
Pion Capture.
Arrival of m/ at stopping target
Dec. 3, 2012
R. Ray - CSN1 Presentation
17
Project Scope
Scope of the Project includes the Mu2e
apparatus (solenoids, detectors)
accelerator modifications, new detector
hall that is part of Fermilab’s new Muon
Campus.
Mu2e
Dec. 3, 2012
R. Ray - CSN1 Presentation
18
Mu2e Project Status
• The Mission Need (CD-0) for Mu2e was established in Nov.
2009.
• The Mu2e cost and schedule range (CD-1) was approved in
July 2012.
• Establish Performance Baseline (CD-2) in Spring of 2014
 Important to understand all contributions to the Project on this time
scale
• The Department of Energy has provided us with a preliminary
funding profile for $230M.
• The Mu2e Project has thus far received $68M of this funding,
representing a significant commitment from the DOE.
• Mu2e enjoys strong support from The Department of Energy,
Congress and Fermilab.
Dec. 3, 2012
R. Ray - CSN1 Presentation
19
L2 Managers
1
Project
Management
R. Ray
FNAL
Dec. 3, 2012
2
Accelerator
S. Werkema
FNAL
3
Conventional
Construction
T. Lackowski
FNAL
6
Tracker
7
Calorimeter
A. Mukherjee
FNAL
S. Miscetti
Frascati
8
Cosmic Ray
Veto
C. Dukes
UVa.
R. Ray - CSN1 Presentation
4
Solenoids
M. Lamm
FNAL
5
Muon
Channel
G. Ginther
FNAL
9
Trigger and
DAQ
M. Bowden
FNAL
20
Schedule
CD-3a CD-2/3b
CD-1
CD-3
CD-4
R&D
Start running beam to
detector in summer of 2019
Engineering Design of Solenoids
Fabricate and QA
Superconductor
Solenoid Fabrication and QA
Site work/Detector Hall Construction
Solenoid
Installation
Detector Construction
Install
Solenoid
Infrastructure
Detector
Field Mapping
Detector
Hall Design
Accelerator and Beamline
Q3 Q4 Q1 Q2 Q3 Q4 Q1
Q2 Q3 Projects
Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3
Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Common
g-2 Commissioning/Running
FY13
Dec. 3, 2012
FY14
FY15
FY16
FY17
R. Ray - CSN1 Presentation
FY18
FY19
FY20
21
Solenoid Status
• Significant engineering and design effort. ~25 FTEs now
engaged in solenoid effort.
• Embarking on a year of conductor R&D to validate design
prior to fabrication of the solenoids.
 Purchasing samples of all 4 solenoid conductor types.
• Detector Solenoid and Production Solenoid to be built in
industry (possibly even in Italy!).
• Transport Solenoid still under discussion.
Dec. 3, 2012
R. Ray - CSN1 Presentation
22
Tracker Status
• T-Tracker was presented as the baseline at DOE Review
in June.
 Straw tubes transverse to solenoid axis.
 Considerable work on design and simulations over the past 3
years.
• I-Tracker proposed as an alternative
 Significant R&D on a design relevant for both Mu2e and MEG.
o Significant synergy from INFN perspective.
 Simulation work not as far along as T-Tracker, but catching up.
Dec. 3, 2012
R. Ray - CSN1 Presentation
23
Tracker Status
• Collaboration evaluating whether I-Tracker satisfies
physics requirements
 I-Tracker resolution is similar to T-Tracker. Significantly more hits
leads to more robust pattern recognition and track fitting that
could lead to reduced backgrounds.
 Collaboration will finish evaluation by end of December.
• Project will make final decision if I-Tracker determined to
satisfy physics requirements.
 Final decision made on the basis of cost, schedule, risk.
Dec. 3, 2012
R. Ray - CSN1 Presentation
24
Calorimeter Status
• Managed by INFN – S. Miscetti is the System Manager
• LYSO chosen as calorimeter element.




High light output
Radiation hard
Small RM
Fast decay time
• LYSO is more expensive than lead-tungstate but the
significantly increased light output and radiation hardness
simplify the design and saves money elsewhere.
 Operate at room temperature
 Use of a simple voltage amplifier in place of a charge sensitive
amplifier and shaper
 Smaller area photodetectors
 No loss of running time to recover from radiation damage.
Dec. 3, 2012
R. Ray - CSN1 Presentation
25
Beam Test
Ratio of crystal response
to beam energy
• March 2011 test of a LYSO array using the
tagged photon beam at the Mainz Microtron.
• Funded entirely by INFN
• Test of energy, timing and position resolution
• Test of photodetector candidates
• Prototype HV boards
• Excellent training ground for students and
post docs who participated in the beam test
and who simulated test array.
• Good agreement between data and
simulations.
• Another beam test to take place in the next
year.
Dec. 3, 2012
R. Ray - CSN1 Presentation
Position Resolution
26
Calorimeter Geometry
• Vane and disk geometry both
under consideration.
• Disks have higher acceptance
and are symmetric to electrons
and positrons.
• However, neutrons are more
problematic for disks.
• Collaboration producing
simulations to study the issue.
• Expect a final decision early in
2013.
Dec. 3, 2012
R. Ray - CSN1 Presentation
27
Importance of Calorimeter
• The calorimeter provides an important cross-check for the
energy, position and timing of conversion electrons.
• Can be integrated into the reconstruction along with the
tracker to provide an unambiguous space point and T0 to
help eliminate left-right ambiguities and make for more
robust track finding.
• The calorimeter can provide a simple trigger for
conversion electron candidates and can provide an
unbiased trigger to to calibrate the tracker.
• Mu2e budget cannot currently support the full cost of the
calorimeter, so INFN contribution can add significant
value and capability to the experiment.
Dec. 3, 2012
R. Ray - CSN1 Presentation
28
INFN Contributions
• INFN is fully integrated into the Project and the
Collaboration with representation on the Mu2e Technical
Board, Institutional Board and Executive Committee.
• Significant Mu2e Contributions from





Laboratori Nazionali di Frascati
Istituto Nazionale di Fisica Nucleare Lecce
Istituto Nazionale di Fisica Nucleare, Pisa
Università del Salento
Università di Udine and INFN Trieste/Udine
• INFN Genova has recently engaged to help on the
solenoids.
Dec. 3, 2012
R. Ray - CSN1 Presentation
29
INFN Contributions
• Frascati




Project Management of calorimeter system
Crystal R&D
Design of mechanical support
Photodetector R&D
• Pisa




Crystal R&D
Cluster reconstruction and analysis software
Low Voltage
Waveform digitizer studies
• Udine
 SiPM R&D for the Calorimeter and radiation hardness testing
Dec. 3, 2012
R. Ray - CSN1 Presentation
30
INFN Contributions
• Lecce/Salento




I-Tracker design and R&D
Simulations of I-Tracker
T-Tracker
Broad array of simulations for trackers, calorimeter, neutron
production, etc.
• Genova
 Proposes to play an important role in the solenoids including
contributions to conductor and coil R&D.
Dec. 3, 2012
R. Ray - CSN1 Presentation
31
Summary
• The physics addressed by Mu2e is extremely compelling.
This is a discovery experiment.
• Mu2e is complementary to MEG and the LHC and is
important in any scenario.
• The Mu2e Project enjoys significant support from the US
Department of Energy, Congress and Fermilab.
• INFN is fully integrated into Mu2e and is playing a critical
role on several fronts.
• A contribution from INFN towards the calorimeter adds a
significant capability that may not be possible otherwise.
Dec. 3, 2012
R. Ray - CSN1 Presentation
32