Atlas TTbar to Tau Analysis

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Atlas TTbar to Tau Analysis. William P. Edson , Teeba Rashid Adviser: Mohammad Sajjad Alam State University of New York at Albany Anirvan Sircar Adviser: Dick Greenwood Loisianna Tech April 14, 2013. ttbar to tau Interaction Overview. q. W +. t. q ’. b. bbar. tbar. W -. - PowerPoint PPT Presentation

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Atlas TTbar to Tau Analysis

Atlas TTbar to Tau AnalysisWilliam P. Edson, Teeba RashidAdviser: Mohammad Sajjad AlamState University of New York at AlbanyAnirvan SircarAdviser: Dick GreenwoodLoisianna TechApril 14, 20131ttbar to tau Interaction OverviewtW+btbarW-bbar -qq2

Top Pair Branching Fractions for ttbar decays[5]CutflowC0: GRLC1: TriggerC2: Primary vertex with ntracks > 4 C3: Electron/muon overlap, larVeto C4: Jet cleaningC5: Lepton Veto C6: njets >= 4 with eta < 2.3 and |jvf| > 0.75C7: MET > 60GeVC8: ptmiss significance > 8C9: MT < 70GeVC10: Sum ET < 500GeVC11: >= 1 bjet (MV1 > 0.601713)C12: Tau n 1, BDTScore > 0.7C13: Trigger matched tau n 1 and pT >= 40GeVC14: MC tau object matchBackgroundsQCD multi-jetestimated contribution determined via data driven techniquesW + jetsZ + jetsDibosonttbar decay (muons and electrons)4QCD multi-jet not modeled well in MC following selection criteria4ABCD RegionsSignal Region (A):BDTScore > 0.7 and Closest Top Mass < 230GeVBackground Regions (B, C and D):B: BDTScore < 0.7 and Closest Top Mass < 230GeVC: BDTScore > 0.7 and Closest Top Mass >230GeVD: BDTScore < 0.7 and Closest Top Mass > 230GeVBDTScore per RegionClosest Top Mass per RegionTop Mass with Highest pT b-jet per RegionTop Mass with Second Highest pT b-jet per RegionMjj per RegionMC Subtraction HistogramsBDTScore per RegionClosest Top Mass per RegionTop Mass with Highest pT b-jet per RegionTop Mass with Second Highest pT b-jet per RegionMjj per RegionCutflow -> Teeba Rashids AnalysisNo cutC0:Event Cleaning: GRL && larError!=2C1:TriggerC2: Primary vertex, ntr >4C3 :LAr FEBC4: Event Cleaning: JetsC5: Jets: > = 4 jetsC6: ==1 TauC7: lepton vetoC8: MET > 60C9: sumPt > 0C10: Pt miss significance > 13C11: >=1 bC12: mt 120 - 240

17Sources of Uncertainty % Uncertainty Jet Energy Resolution +/-1.33 Jet Energy Scale +-/11 Jet Reconstruction Efficiency +/-0.39 B-JES +0.23 -0.30 Pdf In Progress QCD In Progress MC generator +/- 4.91 ISR/FSR Obtained Numbers/ some doubts to obtain the final Value Pile up In Progress JVF In Progress MET In Progress Parton Shower Obtained Numbers /some doubts to obtain final value Tau ID efficiency In Progress Tau Energy Scale In Progress Etmiss uncertainty In Progress

18Cross-Section Measurementtt = 147.06 13 (stat) pb

SM Prediction tt = 166.8 +17.3 18.4 pb (Eur. Phys. J.C63:189-285, 2009)

Nikhef ( + jets) tt = 194 18 (stat) pb (arXiv:1211.7205v1)

+ tt = 186 13 (stat) 20 (syst) pb (Phys. Lett. B 717 (2012) 89-108) 19Conclusions20ThanksDr. Sajjad AlamDr. Pat SkupicDr. Dick GreenwoodCatrin Berniusttbar to tau group21Referenceshttps://twiki.cern.ch/twiki/bin/viewauth/Atlas/WorkBookhttp://atlas.web.cern.ch/Atlas/SUB_DETECTORS/TILE/[1] Marion Lambacher, Study of fully hadronic ttbar decays and their separation from QCD multijet background events in the first year of the ATLAS experiment. July 2007. http://edoc.ub.uni-muenchen.de/7603/1/Lambacher_Marion.pdf.[2]CTEQ. http://www.phys.psu.edu/~cteq/.[3] V. Chekelian, Standard model physics at HERA. 2001. hep-ex/0107053.[4]http://pdg.lbl.gov/[5]Neil Collins, TopCross Section (Current Status and Early LHC Prospects). 10 March 2010. http://www.ep.ph.bham.ac.uk/general/seminars/slides/neil-collins-100310.pdf[6]Zofia Czyczula, Search for New Physics in Tau-pair Events in ATLAS at the LHC. June 2009. http://cdsweb.cern.ch/record/1204789/files/CERN-THESIS-2009-078.pdf[7]Noel Dawe, Tau Identification with Boosted Decision Trees. 18 March 2010.[8]Bjorn Gosdzik, Tau Reconstruction at the ATLAS experiment. 22 January 2009. http://wwwiexp.desy.de/studium/seminare/studsem/ws2008/talks/vortrag09-gosdzik.pdf[9] http://lhc-machine-outreach.web.cern.ch/lhc-machine-outreach/[10] http://public.web.cern.ch/public/en/lhc/lhc-en.html[11] http://www.uslhc.us/[12] http://atlas.web.cern.ch/Atlas/Collaboration/[13] https://twiki.cern.ch/twiki/bin/viewauth/Atlas/InnerDetector[14] The ATLAS Liquid Argon Calorimeter at the LHC: Overview and Performance Mathieu Aurousseau, http://cdsweb.cern.ch/record/1270159/files/ATL-LARG-SLIDE-2010-119.pdf[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/[19] The ATLAS Experiment at the CERN Large Hadron Collider. 2008. http://iopscience.iop.org/1748-0221/3/08/508003 [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. http://www.scholarpedia.org/article/Introduction_to_Parton_Distribution_Functions[24] CMS collaboration, First Measurement of the top quark pair production in the dilepton channel with tau leptons in the final state in pp collisions at s = 7 TeV. CMS-PAS-TOP-11-06[25] Interactions.org, Particle Physics Glossary. 2009. www.interactions.org/cms/?pid=1002289[26] David Griffiths, Introduction to Elementary Particles. 2004. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim[27] Noel Dawe, Dugan ONeil, 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.meta-synthesis.com/webbook/35_pt/pt_database.php?Button=Misc+PTs[30] Arghir, S; Behar, S; Cavaliere, V; Coadou,Y ; Czodrowski, P; Flechl, M; Kopp, A; McCarn, A; zur Nedden, M ;Neubauer, M; Randle-Conde, A; 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 states. 31 March 2011. https://cdsweb.cern.ch/record/1312955?22Back-ups

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