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Atlas TTbar to Tau Analysis

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 -.

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Atlas TTbar to Tau Analysis

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  1. Atlas TTbar to Tau Analysis William P. Edson, Teeba Rashid Adviser: Mohammad SajjadAlam State University of New York at Albany AnirvanSircar Adviser: Dick Greenwood Loisianna Tech April 14, 2013

  2. ttbar to tau Interaction Overview q W+ t q’ b bbar tbar W- ντ τ- Top Pair Branching Fractions for ttbar decays[5]

  3. Cutflow • 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

  4. Backgrounds • QCD multi-jet • estimated contribution determined via data driven techniques • W + jets • Z + jets • Diboson • ttbar decay (muons and electrons)

  5. ABCD Regions • Signal Region (A): • 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

  6. BDTScore per Region

  7. Closest Top Mass per Region

  8. Top Mass with Highest pT b-jet per Region

  9. Top Mass with Second Highest pT b-jet per Region

  10. Mjj per Region

  11. MC Subtraction Histograms

  12. BDTScore per Region

  13. Closest Top Mass per Region

  14. Top Mass with Highest pT b-jet per Region

  15. Top Mass with Second Highest pT b-jet per Region

  16. Mjj per Region

  17. Cutflow -> Teeba Rashid’s Analysis • No cut • C0:Event Cleaning: GRL && larError!=2 • C1:Trigger • C2: Primary vertex, ntr>4 • C3 :LArFEB • 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 • C12: mt120 - 240

  18. Sources 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

  19. Cross-Section Measurement • σtt= 147.06 ± 13 (stat) pb • SM Prediction σtt = 166.8 +17.3 – 18.4 pb (Eur. Phys. J.C63:189-285, 2009) • Nikhef (τ + jets) σtt = 194 ± 18 (stat) pb(arXiv:1211.7205v1) • μ+ τσtt = 186 ± 13 (stat) ± 20 (syst) pb (Phys. Lett. B 717 (2012) 89-108)

  20. Conclusions

  21. Thanks • Dr. SajjadAlam • Dr. Pat Skupic • Dr. Dick Greenwood • CatrinBernius • ttbar to tau group

  22. References • https://twiki.cern.ch/twiki/bin/viewauth/Atlas/WorkBook • http://atlas.web.cern.ch/Atlas/SUB_DETECTORS/TILE/ • [1] Marion Lambacher, Study of fully hadronicttbar 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]ZofiaCzyczula, 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 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.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; zurNedden, 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?

  23. Back-ups

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