Archana Sharma, Suman Beri Panjab University, Chandigarh

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A data-driven performance evaluation method for CMS RPC trigger system & Study of Muon trigger efficiencies with official Tag & Probe package for ICHEP. Archana Sharma, Suman Beri Panjab University, Chandigarh. CMS Muon System. DT. - PowerPoint PPT Presentation

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  • A data-driven performance evaluation method for CMS RPC trigger system&Study of Muon trigger efficiencies with official Tag & Probe package for ICHEPArchana Sharma, Suman BeriPanjab University,Chandigarh

  • CMS Muon System*6 gaps (Layers) for each camber1 wire plane and 1 cathode plane with strips~100 m spatial resolution

    CSC2 RPC chamber for the first 2 DT stations1 RPC chamber for the last 2 DT stations and for the CSC chamber till ||

  • CMS Muon TriggerMuon trigger processing is delivered in two different stages:Regional Trigger (subdetector-wise) data processingGlobal Muon Trigger algorithm processing (merginginformation by the muon subdetectors)Regional Triggers:DT & CSC provide up to four regional trigger candidatesRPC provide up to four regional trigger candidates both in the barrel and endcap regionsThe candidates are selected according to highest pT and best measurement qualityGlobal Muon Trigger (GMT) algorithmCollects regional triggers informationThe algorithm outputs GMT candidates seeking for good quality (regional) trigger candidates.A GMT candidate can be the result ofSingle detector measurement orTwo complementary detectors measurements (RPC&DT or RPC&CSC)Transmits up to 4 GMT candidates to L1 decision logic

    Muon Trigger Data Flow

  • A Data Driven trigger performance evaluation methodGMT algorithm keeps trace of the muon sub-system which provided the candidates measurement(s)Such feature can be exploited for evaluating in a data-driven fashion the trigger performance of each muon sub-systemBy considering the trigger candidates provided by a given sub-detector using its complementary one as reference.MotivationSuch method is relevant in cross section calculation scenarios, for trigger efficiency evaluation unbiased by MC guesses*

  • Method implementationFor RPC trigger performance evaluationall the events with GMT candidates provided by the DTs in barrel or CSCs in endcaps are selectedamongst these, the number of events with candidates provided also by RPC is counted up. With such approach only RPC regional candidates good enough to be accepted by GMT are accounted forThus the method measures the actual contribution of RPC system trigger to the L1 final decisionFurthermore GMT candidate is required to fulfill at least one L1 muon paths in the Global Trigger (GT) table.*

  • Analysis features and tasksMethod validated with Monte Carlo:Sample simulating pp W+X +X processHigh Transverse momentum (70-200 GeV/c) single muon eventsLow Transverse momentum (0-10 GeV/c) single muon eventsPythia 6.Detectors response simulation with GEANT4RPC detectors efficiency plugged in the simulation is 95%.Results of data-driven method compared with a classic MC-truth performance evaluation

    GoalAchieve agreement between two methodsFlat efficiencies curves over pT range*Mean 32.02RMS 12.86pT spectrum of muons from W

  • Events with just one stand-alone muon are selectedGMT candidate extracted from muon track seed information*Data-driven methodGMT residuals with respect to STAND-ALONE MUONS

    Mean 0.000978RMS 0.05628

  • Events with just one generated muon are selectedThe number of events with L1-accepted GMT candidates with RPC contribution is counted up*MC-truth methodGMT residuals with respect to GENERATED MUONS

  • RPC Trigger from GMT data-driven and MC-truth efficiencies (pseudorapidity)*

  • Geometrical cracks along (wheels transition) and between different sectors in are the source of mismatchesIn order to study the goodness of the methodFocus on the range ||
  • *RPC Trigger from GMT efficiencies in with ||
  • Efficiency with respect to pt after applying all sets of cuts for overall pt rangeFor positive muons

  • For negative muons

  • Summary and perspectivesData-driven method measuring RPC trigger effectiveness in CMS muon frameworkFulfilling GMT and L1 requirements in trigger stageProviding information employed in stand-alone reconstruction seeding and cuts improvethe matching between the two curvesefficiencies.RPC Trigger efficiency curves after cuts show flat behavior with respect to transverse momentum.The discrimination between differently charged muons yielded a clearer picture of detector behavior for low pT muons.Different ranges are affected by cracksFor low momentum regions and also on the edges of momenta range for muons from W decay results are effected by the statistical fluctuations and also smaller probability of low momentum muons to hit enough chambers to create a trigger.

    Work in progressUse of method for other muon detectors as well and plugging it for physics oriented performance evaluation analysisDelivery of the method for real data applications*

  • Study of Muon trigger efficiencies with official Tag & Probe package for ICHEP

  • Overview of Tag and Probe Method

    Tag and Probe method is a data-driven approach to estimate the efficiencies of the different processes which involves a particle reconstruction in a detector.Very tight selection criteria: TagPaired with tag to fulfill resonance mass window: probe (loose selection criteria) = Npass/ Npass + Nfail

  • Analysis FeaturesCMSSW_3_6_1_patch4Set of tag used PhysicsTools/TagAndProbe V02-04-06 MuonAnalysis/MuonAssociators V01-07-04 MuonAnalysis/TagAndProbe V06-05-05Sample used for Jpsi study :MC /JPsiToMuMu_2MuPEtaFilter_7TeV-pythia6-evtgen/StoreResults-Spring10_skimJPsiLoose_v3-8b75d8af690cce599c8716d67f1bedfa/USERData Skimmed Jpsi samples for runs from 132440-134987, 13509-135175, 135445-135575, 135735, 136033-136082, 136087-136119, 137027-137028 Sample used for Zmumu peak:MC sample : /Zmumu_M20_CTEQ66-powheg/Summer10-SART36_V9_S09-v2/GEN-SIM-RECOData samples Runs used to collect data are 135149, 136087, 137028, 138737, 138748, 138750, 138751, 138919, 138939, 139096, 136033, 136100, 139103, 136665, 136805, 139195, 139360, 139372, 139459, 139779, 139790, 139965, 139971, 139972, 139980, 140331, 140058, 140076, 140116, 140126, 140133, 140158, 140159, 140182, 140334, 140387

  • Sets of cuts used for HLT_Mu9 efficiency with Jpsi peakCuts on the TagGlobal MuonPt >3 GevPassing HLT_Mu3 triggerPassing Track quality Cuts (numberOfValidHits > 11 + pixelhits> 1 +normalizedChi2 < 4 + |d0| < 3 + |dz| < 30)Cuts on Probept>10 GeV|eta| 10 + pixelhits> 1 +normalizedChi2 < 10 + |dxy|1 + number of valid hits in Global track >0)

  • The statistics & Efficiency for HLT_Mu9 for Data sample

    Without IsolationWith IsolationTotal eventspassFailEfficiencyTotalPassFailEfficiencyTotal eta region2219386.4%+-7.3%76185.7%+-13.2%Barrel region440100%000-Overlap region770100%330100%Endcap region118372.7%+-13.4%43175%+-21.6%

  • The statistics & Efficiency for HLT_Mu9 for MC Jpsi sampleMC efficiency using Tag & Probe with j/psi peak is lower than the efficiency from matching method (around 93%). So the j/psi peak is not so good to estimate the HLT_Mu9 trigger efficiency with VBTF selection.

    Without IsolationWith IsolationTotal eventspassFailEfficiencyTotalPassFailEfficiencyTotal eta region4881420267986%+-.51%2900252038087%+-.63%Barrel region1763165410993.7%+-.59%8948514395.1%+-.72%Overlap region108588520081.3%+-1.2%64653910783.2%+-1.5%Endcap region2033166337082%+-.88%1360113023083.2%+-1.0%

  • Sets of cuts used for HLT_Mu9 efficiency with Zmumu peakSame set of cuts are applied on Tag muon and Probe muonpt>20 GeV|eta| 10 + pixelhits> 1 +normalizedChi2 < 10 + |dxy|1 + number of valis hits in Global track >0)4) No Isolation condition is applied.5) Tag should pass HLT_Mu9 trigger.

    *

  • HLT_Mu9 (L1+HLT) trigger efficiency with respect to eta for different pt bins

  • HLT_Mu9 (L1+HLT) trigger efficiency with respect to pt for different eta bins

  • SummaryVery few statistics till now for Jpsi so hoping that we can collect more data to make the results better.As explained earlier also efficiency with MC sample of Jpsi comes lower then matching method. That's why we have shifted our study to high pt region (Zmumu peak).The present study is the first look with real high pt muons from Zmumu candidates . Next step is to update the results with more data.The average efficiency of HLT_MU9 trigger with MC Zmumu sample is around 93% which is in agreement with matching method. In the barrel part efficiencies with data are MC are in close agreement with matching method. We are investigating the reasons of low efficiencies in endcaps.

    Entries 850000Mean 32.02RMS 12.86 **For positive muons*MC efficiency using t&p and j/psi peak is different from matching method: matching method 93%, t&p 87%. So the j/psi peak is not so good to estimate the HLT_Mu9 trigger efficiency with VBTF selection.*