William P. Edson, Teeba Rashid
Adviser: Mohammad Sajjad Alam
State University of New York at Albany
Anirvan Sircar
Adviser: Dick Greenwood
Loisianna Tech
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q
q’
Top Pair Branching Fractions for ttbar decays[5]
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C0: GRL
C1: Trigger
C2: Primary vertex with ntracks > 4
C3: Electron/muon overlap, larVeto
C4: Jet cleaning
C5: Lepton Veto
C6: njets >= 4 with eta < 2.3 and |jvf| > 0.75
C7: MET > 60GeV
C8: ptmiss significance > 8
C9: MT < 70GeV
C10: Sum ET < 500GeV
C11: >= 1 bjet (MV1 > 0.601713)
C12: Tau n ≥ 1, BDTScore > 0.7
C13: Trigger matched tau n ≥ 1 and pT >= 40GeV
C14: MC tau object match
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QCD multi-jet
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estimated contribution determined via data driven
techniques
W + jets
Z + jets
Diboson
ttbar decay (muons and electrons)
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Signal Region (A):
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BDTScore > 0.7 and Closest Top Mass < 230GeV
Background Regions (B, C and D):
B: BDTScore < 0.7 and Closest Top Mass < 230GeV
 C: BDTScore > 0.7 and Closest Top Mass >230GeV
 D: BDTScore < 0.7 and Closest Top Mass > 230GeV
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No cut
C0:Event Cleaning: GRL && larError!=2
C1:Trigger
C2: Primary vertex, ntr >4
C3 :LAr FEB
C4: Event Cleaning: Jets
C5: Jets: > = 4 jets
C6: ==1 Tau
C7: lepton veto
C8: MET > 60
C9: sumPt > 0
C10: Pt miss significance > 13
C11: >=1 b
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Sources of Uncertainty
% Uncertainty
Jet Energy Resolution
Jet Energy Scale
Jet Reconstruction Efficiency
B-JES
Pdf
QCD
MC generator
ISR/FSR
obtain the final Value
Pile up
JVF
MET
Parton Shower
obtain final value
Tau ID efficiency
Tau Energy Scale
Etmiss uncertainty
+/-1.33
+-/11
+/-0.39
+0.23 -0.30
In Progress
In Progress
+/- 4.91
Obtained Numbers/ some doubts to
In Progress
In Progress
In Progress
Obtained Numbers /some doubts to
In Progress
In Progress
In Progress
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σtt = 147.06 ± 13 (stat) pb
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SM Prediction σtt = 166.8 +17.3 – 18.4 pb
(Eur. Phys. J.C63:189-285, 2009)
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Nikhef (τ + jets) σtt = 194 ± 18 (stat) pb
(arXiv:1211.7205v1)
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μ+ τ σtt = 186 ± 13 (stat) ± 20 (syst) pb
(Phys. Lett. B 717 (2012) 89-108)
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Dr. Sajjad Alam
Dr. Pat Skubic
Dr. Dick Greenwood
Catrin Bernius
ttbar to tau group
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https://twiki.cern.ch/twiki/bin/viewauth/Atlas/WorkBook
http://atlas.web.cern.ch/Atlas/SUB_DETECTORS/TILE/
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[15] http://atlas.ch/
[16] ATLAS Tile calorimeter commissioning status and performance – Ana Henriques, http://cdsweb.cern.ch/record/1213918
[17] Muon Spectrometer Technical Design Report, http://atlas.web.cern.ch/Atlas/GROUPS/MUON/TDR/Web/TDR_chapters.html
[18] http://atlas-magnet.web.cern.ch/atlas-magnet/
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[20] CERN faq LHC the guide. http://multimedia-gallery.web.cern.ch/multimedia-gallery/Brochures.aspx
[21] Jane T. Bromley.,Investigation of the Operation of Resistive Plate Chambers. September 1994. www.hep.man.ac.uk/theses/jane.pdf
[22] Joel Feltesse, Introduction to Parton Distribution Functions. Scholarpedia. 6 November 2010.
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at √s = 7 TeV. CMS-PAS-TOP-11-06
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[26] David Griffiths, Introduction to Elementary Particles. 2004. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
[27] Noel Dawe, Dugan O’Neil, Tau Identification with Boosted Decision Trees. 15 July 2010.
https://indico.cern.ch/getFile.py/access?contribId=18&resId=0&materialId=slides&confId=95501
[28] Michael Wright, Exclusive Jet Study with Kt, AntiKt and Cambridge Aachen Jet Finders. 10 June 2010.
https://ppes8.physics.gla.ac.uk/twiki/bin/view/ATLAS/ExclusiveJetStudy#AntiKt_Jet_Finder
[29] Mark R. Leach, The INTERNET Database of Periodic Tables. 1999-2001. http://www.metasynthesis.com/webbook/35_pt/pt_database.php?Button=Misc+PTs
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Rozen, Y; Sekula, S; Takahashi, Y; Tomoto, M; Vickey, T; Xella, S, Data-driven estimation of the background to H+ searches with hadronic-tau final
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