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EWK Physics

EWK Physics. Physics of/with W and Z. Using W/Z for PDFs Arie Bodek. Early Z Reconstruction. CMS is optimized for W and Z physics Z reconstruction is especially easy. electrons. muons. Early W Reconstruction. Muon channel shows a clean signal. Electron channel needs improvement

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EWK Physics

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  1. EWK Physics Physics of/with W and Z Using W/Z for PDFs Arie Bodek Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  2. Early Z Reconstruction • CMS is optimized for W and Z physics • Z reconstruction is especially easy electrons muons Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  3. Early W Reconstruction Muon channel shows a clean signal. Electron channel needs improvement Tighten electron identification criteria to reduce QCD BG Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  4. Tighter electron ID for Wenu Georgios Daskalakis et al 14 TeV , 10pb-1 14 TeV , 10pb-1 S = 58091 B = 64730 S/B = 0.9 S = 45564 B = 30309 S/B = 1.5 Single Isolated Electron HLT GsfElectrons in ECAL fiducial with ET>20.0 GeV Σ[(PTctf/PTgsf)2]<0.005, 0.02<ΔR<0.6 e/γ-POG default “Tight” electron ID Single Isolated Electron HLT GsfElectrons in ECAL fiducial with ET>20.0 GeV Σ[(PTctf/PTgsf)2]<0.005, 0.02<ΔR<0.6 H/E σηη ΔφInΔηIn B 0.026 0.0092 0.007 0.0030 E 0.018 0.0250 0.007 0.0040 Signal: ReReco 10pb-1 scenario Background: Gumbo soup 10pb-1 scenario Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  5. Background MET & Wenu MET CMS PAS EWK-07-001 D.Wardrope Background MET template is estimated by inverting the isolation cut. Other combinations are also under test involving MT, electron ID variables. Techniques to remove possible correlations are under study. For the estimation of the Wev MET, the γ*/Ζee is used by treating one electron as “neutrino”. New results available using :- 10pb-1 scenario - corrections for the W mass - corrections for the neutrino acceptance Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  6. T&P : selection efficiencies Preselection Efficiency Claire Timlin Me,e (GeV) In process of repeating efficiency estimations using 10pb-1 scenario data. Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  7. Full Z reco vs +SA vs +Trk Francesco Fabozzi et al ZToMuMu skims Signal and bkg 10 pb-1 ReReco samples Latest reprocessed samples in 1_6_x release ppmuX sample now available ppmuX is the dominant bkg for the ZMuTrk selection Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  8. Zactivities and plans Francesco Fabozzi et al • Study to improve fitting strategy • A more powerful fitting package has been released for these studies • https://twiki.cern.ch/twiki/bin/view/CMS/ZMassFitStudies • Selection refinements • Tighten Pt isolation on ZMuTrk? • Study calorimeter isolation when released in AOD • Bkg studies • Remove same charge requirements from the ZMuMu skim and run a first test production Much of this group is derived from DT community. CSC community members may want to join this effort soon.Expect some from high pT dimuon resonance searchers to do so. Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  9. Zeh Visible Mass Kostas Petridis Potential for seeing the signal However, BG uncertainties not well studied Trigger and reconstruction improvements not yet used

  10. Zh Visible Mass Letizia Lusito Again, potential for seeing a signal demonstrated However, BG evaluation not complete Improved t reconstruction yet to be used

  11. Ze Visible Mass Bansal, et al Same issues as te+th and tm+th

  12. Jets Studies (SisCone) validation Preliminary studies for Wmn +Jets selector QCD(new), Z, ttbar BKGs Update on Zmm +Jets selector – Brief update on fits Fits including selected BKGs (Z, ttbar) Fit Variations W & Z + jets Studies Ilaria Segoni Maurizio Pierini Maria Spiropulu Thiago Tomei … (CERN & Friends) Wisconsin, LLNL, ETH-Zurich and Roma are beginning to work in this area with W/Z to electron channels. Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  13. Di-Muon Mass Ilaria Segoni Z+2Jets Z+1Jet Z+3Jets Z+4Jets Z+5Jets Histograms relative to the three processes are plotted independently Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  14. MLL Fit: Z + 1 jet Ilaria Segoni & Maurizio Pierini Fit Results: NSignal=8917+-154 NBkg=2940+-133 M=91.01+-0.05 GeV/c2 s=3.02+-0.15 GeV/c2 BW Width fixed at 2.4981 GeV Preliminary Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  15. Z+2Jets (3 Fit Functions) Ilaria Segoni & Maurizio Pierini 1) “Standard” Fit ( Fixed Params: BW M and G, Gauss s ) 2) Gauss s free to float 3) Gauss s & BW M free to float 1) 2) 3) Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  16. dN(Z+Jets)/dNJets Ilaria Segoni & Maurizio Pierini Floating s for all Jet Mult Standard Fit 2) 1) • Fit is to AeB • B = -1.61 +- 0.03  slope=5.00 • B = -1.62 +- 0.04  slope=5.05 • B = -1.61 +- 0.03  slope=5.00 Floating s and BW M for all Jet Mult 3) Results are robust versus different fit choices Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  17. W Trans. Mass vs Jet Mult. Ilaria Segoni • Dataset: Alpgen CSA07 Soup containing: • W+Jets • Z+Jets • ttbar+Jets • HLT Requirement: Logical “OR” between all Muon HLT paths W+1Jet top exceeds W at >= 3Jets W+3Jets W+2Jets Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  18. Rates vs Jet Multiplicity Ilaria Segoni With Single Mu Req. W/O Single Mu Req Number of events Number of events Inclusive Jet Multiplicity Inclusive Jet Multiplicity Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  19. Signal & QCD Rates @ 100/pb Ilaria Segoni QCD background larger than expected in previous study. Should update the MC results soon Opportunity to join the effort … Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  20. Diboson Analyses Vuko Briglevic All channels covered, but some just beginning • ZZ well advanced • Florida, Saclay, Taiwan • WZ and WW: progressing • WZ: Zagreb, Kansas, CERN • WW: UCSB, UCSD, Fermilab, Purdue • Z: started • Athens, Belgrade, Taiwan, India, (Jonathan) • W: about to start • Athens, India, (Jonathan) Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  21. ZZ  4  Alexei Drozdetskiy Signal Zbb ttbar A.Drozdetskiy, A.Korytov et al cuts Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  22. DY Studies Dimitriy Bourilkov • Dimitri Bourilkov leading effort • Covers the Mll spectrum below and above Z • Started work recently • Generator studies • 10 TeV vs 14 TeV • Additional effort welcome / required • High interest at startup • Jessica Leonard (ee) • Kristian Kotov (mm) Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

  23. PDF Studies • Asymmetry in production of W+ and W– can constrain d versus u in proton • Asymmetry in muon channel being studied • O(1) fb–1 or more needed for constraining PDFs • However, differences from expectations from global PDF fits should be looked at from startup • Similarly Z forward-backward asymmetry can constrain Parton Distribution Functions • Z pT distribution can be used to constrain gluon distribution • Arie Bodek will help supervise postdocs and students working on these analyses • Bodek lead similar analyses at CDF and is PDF expert Sridhara Dasu (Wisconsin), Juan Alcaraz (CIEMAT)

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