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Trigger efficiency with UED SS dimuon events

Trigger efficiency with UED SS dimuon events

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Trigger efficiency with UED SS dimuon events

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  1. Trigger efficiency with UED SS dimuon events F. Marinho

  2. Overview • UED Modelreminder • Motivation for triggerstudies • Trigger efficiency vs muon PT • Trigger Paths (Leptonic & Hadronic) • Background

  3. The UED model • Allparticles are allowed to propagate in the extra dimension • KK numberconservation UED pairproductionand LKP • Predictstheproductionofthe N=1 modesat LHC energies • Interestingphenomenology. In some aspects similar to SUSY models

  4. ThemUEDmodel Ecm = 7 TeV • Parameters: 1/R,  • HighXSectionvaluesdependon 1/R • PT distributions in thelow GeV range • Triggerstrategyshouldnotcutthosemuons Reconstructed

  5. Data sets • Used CMSSW_3_3_6: Fastsimulationwithstartup setup + trigger • EventsgeneratedwithPythiaonly • UED ssdimuons: 1/R: 300, 500, 700, 900, 1100 ~35000 events per point • ttbar inclusive events225000 events

  6. MuonReconstruction • Reconstructionefficiency as a functionof PT • Muonsatlow range are alreadysuppressed in thereconstruction Muonrequirements: Prompt, Global, MC matched • Triggeralgorithmsshouldnotincreasetheseeffectsabove7GeV

  7. TriggerEfficiency • Throughoutthistalk: • Only Global Muons are used • Trigger denotes theHLT trigger path used • Efficienciesevaluated for leadingandnext to leadingmuons • Bothmuonsreconstructed: 80% ofsignalkept

  8. SingleMuon Paths • HLT Paths highlyefficient for signal • Low PT range notsignificantlyaffectedbytriggercutsup to 5 GeV • PT cutsshouldbe< 7GeV keepingefficiencyabove 80% for thenext to leadingmuon

  9. Dimuon Paths • Highefficiency paths for signal • Dimuon paths have similar effectsonleadingandnext to leadingmuons

  10. MET Paths • Signaleventswithdistinct MET signature • Twolightestparticles • Muonsdistributions are notdistorted

  11. Jet Paths • Signaleventswithdistinct Jet+MET signature • Almostalleventswereaccepted • Muondistributions are recovered • Jet cuts are veryloose in these HLT Paths • More interesting to cutonnumberofjets (offline)

  12. Background ttbar • 5%ofeventswith SS dimuon • Suppressiondue to RECandcharge requirement • Lead muonsfromW’sandb’s • Next to lead muonsfromhadronic • No isolationorothercuts are applied

  13. ttbar - Muon Paths • Distributions similar to signal • Butefficiencies are lower

  14. ttbar – Dimuon Paths • Similar distributions • Lowerplateaus

  15. ttbar – MET Paths • Low PTcorrelation • Good path for robustnesscheck? • Background highlysuppressed • Use as offlineselectionvariable

  16. ttbar - Jet Paths • No PTcorrelation • Good path for robustnesscheck? • Backgroundpartiallysuppressed • Use as offlineselectionvariable

  17. Summary • SS dimuonanalysispromisingalreadyat startup possible to scratchcurrent1/Rlowerlimit • Avoidacceptanceeffects for muondistributionsatleastonofflinelevel • Muontriggers for startup data employed. • Considerhadronic Paths for robustnesspurposes. • MET andJets are interesting as offlineselectionvariables.

  18. Next • Offlineselection • Improve background studies • Determine yieldsat 7 TeV • Yieldsvsmodelparameters • Sameexercise for otherleptons (anyoneinterested???)