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Status of Muon Trigger Efficiency Measurement for ICHEP 2010

This document summarizes the ongoing measurements and efforts related to muon trigger efficiency for top physics analyses, presented during the Trigger Performance Group meeting on June 21, 2010. The report outlines a clear roadmap divided into three steps, detailing steps completed, including a total efficiency assessment and parameterization of trigger efficiency. Results gathered thus far indicate an average efficiency of 94% for high-pT muons. Additional studies on selection criteria, matching efficiency, and ongoing clean-up cut investigations are discussed as well.

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Status of Muon Trigger Efficiency Measurement for ICHEP 2010

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  1. Status of Muon TriggerEfficiencyMeasurementfor ICHEP BenediktHegner, Benjamin Klein, YvonneKüssel, Patricia Lobelle, MarkusMarienfeld, RahmatRahmat, LariaRedjimi, JasonSlaunwhite, SinéadWalsh Trigger Performance Group meeting 21 June 2010

  2. Plans • Roadmap as shown in Jason's talk on 29th of April (slides) • Step1: ~21 May • Total efficiencywith error largeenoughtocoveranyobservedvariation in eta/pt • Step2: ~week of 7 june • Coarseparameterisation of thetriggerefficiency We are close to the initial schedule (slowed down by limited statistics) • Step3: ~end of june • Tag & probewith Z-> mmfrom data • See status reportspresentedbyBenjamin (27 May, slides) and Yvonne (15 June, slides) • Resultscollected in ourtwiki page: https://twiki.cern.ch/twiki/bin/view/CMS/TopMuTrigEff4ICHEP Goal: provide muon triggerefficiencymeasurementfor top analyses Basedonminbias & jet trigger data

  3. Datasets • JetMETTautriggeredsamples • /MinimumBias/Commissioning10-SD_JetMETTau-v9/RECO Runs: 135059, 135149, 135175, 135445, 135521, 135523, 135525, 135528, 135534, 135535, 135537, 135573, 135575, 135735 • /JetMETTau/Run2010A-May27thReReco_v1/RECO Runs: 136033, 136035, 136066, 136080, 136082, 136087, 136088, 136097, 136098 , 136100, 136119, 136294, 136297 ~ 17 nb-1 • Skim • – At least one muon of any kind (global/tracker/standalone) with Pt>5 GeV • – Scraping Veto && Primary vertex filter • – HltPhysicsDeclared (next iteration only relying on good LS) •  AfterSkimming: 34677 events

  4. Muon selection & efficiencydefinition isGlobalMuon && isTrackerMuon Chi2< 10 NvalidMuonHits>0 d 0 <0.2 N hits>=11 RelIso <0.05  No iso cut applied now pT > 5GeV Eta<2.4 • Muon selection as close to the top mu+jets reference as possible with the current available statistics • Currently studying more muon clean-up cuts • Cross check with what’s being done in Muon POG & VBTF Efficiency definition fraction of good selected muons matched to HLT muons in dR<0.2 Matching ~99% efficient • Study HLT_Mu5 • - HLT_Mu9 whenwehave more statistics

  5. HLT_Mu5 Efficiency vs pt, h Overlap Overlap CSC DT CSC

  6. Efficiency vs somecut variables Data vs MC Jet multiplicity Jet definition: Ak5 caloJets Et>30 EmEnergyFraction>0.01 N90hits>1 fHPD<0.98

  7. Additional cuts applied (recommened by Muon POG) on top of the reference selection • to reject punch through and decays in flight S.Walsh Referenceselection Onslide 4

  8. Some more efficiencyplots vs cut variables, comparingthis new selectionwiththeoldone S.Walsh

  9. Comparisonwithttbar MC J.Slaunwhite • Muon trigger efficiency for high-pt muons from ttbar • Non-isolated muons to increase statistics, • Average efficiency is 94% Chi2< 10 d 0 <0.2 N hits>=11 pT > 10GeV Eta<2.4 Sample: /CMSSW_3_6_1/RelValTTbar/GEN-SIM-RECO/MC_36Y_V7A-v1/ - Prompt ttbarmuons are different from the non-prompt muons that exist in the data we've collected so far - We don't necessarily expect the efficiency to be the same without clean up cuts - Studies of clean-up cuts under investigation

  10. General recommendationstobeused in top analyses • Triggers used in top analyses - Muon channels: HLT_Mu9 - Electron channels: HLT_Photon10_L1R up to now, HLT_Photon10_Cleaned_L1R from now on (switch to HLT_Photon15_Cleaned_L1R when it has to be prescaled) • Should we in addition request any other bits (e.g. BSC beam-halo veto on 36||37||38|39 etc ? • Should we request the trigger also in MC or not ask for the HLT bit in MC, but just apply a global scale factor for the inefficiency observed in data (inclusively) ?

  11. Summary • HLT_Mu5 efficiency measurement available • Results are being posted in https://twiki.cern.ch/twiki/bin/view/CMS/TopMuTrigEff4ICHEP • Reasonable agreement with MC • Will compare with similar studies performed in other groups (Muon POG, VBTF) to understand possible differences • …

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