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Vladimir Litvin, Toyoko Orimoto Caltech, CMS QCD Meeting 19 June 2007. High energy photon pairs: L1/HLT Studies. Introduction. Study to investigate L1 and HLT (in)efficiencies and optimize selection for an express stream for very high energy diphoton events MC Samples:
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Vladimir Litvin, Toyoko Orimoto Caltech, CMS QCD Meeting 19 June 2007 High energy photon pairs: L1/HLT Studies
Introduction • Study to investigate L1 and HLT (in)efficiencies and optimize selection for an express stream for very high energy diphoton events • MC Samples: • Produced at Caltech & Fermilab (with no pileup)
Releases and Tags CMSSW_1_3_1_hlt2 with tags: • V00-00-53 HLTrigger/btau • V00-00-26 HLTrigger/xchannel • V01-06-06 RecoLocalTracker/SiPixelClusterizer • V01-00-06 L1Trigger/L1ExtraFromDigis • V02-00-06 L1Trigger/L1ExtraFromMCTruthProd • V00-00-67 HLTrigger/Configuration CMSSW_1_3_1_hlt3 with tags: • V02-00-07 DataFormats/L1Trigger • V01-00-09 L1Trigger/L1ExtraFromDigis • V02-00-09 L1Trigger/L1ExtraFromMCTruthProd • V01-08-00-08 L1Trigger/GlobalCaloTrigger • V00-00-20-01 HLTrigger/HLTanalyzers • V00-04-06-03 HLTrigger/HLTexample • V00-00-02-02 SimCalorimetry/HcalTrigPrimProducers • V00-01-17-02 RecoTauTag/HLTProducers • V00-00-28 RecoEgamma/EgammaHLTProducers • V00-00-06 EventFilter/EcalDigiToRaw • V00-00-01-08 EventFilter/EcalRawToDigiDev • V01-01-09 DataFormats/EcalRawData • V00-00-10 Geometry/EcalMapping • V00-01-32 HLTrigger/Muon • V00-00-07-09 HLTrigger/JetMET • V00-00-33 HLTrigger/Egamma • V00-00-78 HLTrigger/btau • V00-00-40 HLTrigger/xchannel • V00-01-03 HLTrigger/Configuration CMSSW_1_3_1_hlt4 with tags: • V00-00-20-07 L1Trigger/RegionalCaloTrigger • V00-00-34 RecoEgamma/EgammaHLTProducers • V00-03-00 RecoTracker/SpecialSeedGenerators • V00-04-10 RecoMuon/CosmicMuonProducer • V00-02-03-03 RecoMuon/TrackerSeedGenerator; • V00-07-07-05 RecoMuon/GlobalTrackFinder • V00-01-14 HLTrigger/Configuration CMSSW_1_3_1_hlt5 with tags: • V00-01-10 Utilities/ReleaseScripts • V00-01-47 HLTrigger/Muon • V00-00-85 HLTrigger/btau • V00-00-07-15 HLTrigger/JetMET • V01-03-26 HLTrigger/HLTcore • V00-01-41 HLTrigger/Configuration
MC Samples • Signal RS-1 G: • ~80-90k (131_hlt2,3,4) each for 750, 1250, 1000, & 1500 GeV mass samples (with c = 0.1) • Background: • Born: ~100k (131_hlt2,3,4) events • Box: ~300k (131_hlt2) and ~100k (131_hlt3,4) events • CKIN(1) = 200 GeV • low limit of the invariant mass of the two outgoing photons, with high end is set to infinity • Done intentionally to reduce the number of events to produced while keeping the most useful part of the backgrounds for our studies. born box
Invariant Masses Candidates reconstructed from two Island Basic Clusters from ECAL Barrel/Endcap with pt>(30) 100 GeV 720.5 ± 0.1 15.0 ± 0.2 1443.0 ± 0.3 26.6 ± 0.3 960.5 ± 0.2 19.9 ± 0.2 750 1000 1500 Pt_photons > 30 Pt_photons > 100 box born Still need energy correction
HLT Egamma Efficiencies • Egamma efficiencies for CMS_1_3_1 hlt2, hlt3, hlt4 (no H/E) • For 750 GeV signal sample and born and box backgrounds
HLT Egamma Efficiencies • Decrease in EG HLT efficiencies with increasing mass resonance due to tight cut on energy deposition in HCAL for EG objects… • If E > 6 GeV in HCAL for cluster from ECAL Barrel (8 GeV for ECAL Endcap), then the HLT object is considered *not* an EG object.. • Currently this cut is too tight for very high energy diphotons • Utilize an H/E cut instead… • Two additional bits were added in 1_3_1_hlt5 for high energy EM stream, based on a 5% H/E cut
H/E Selection • Check signal and born/box background efficiencies with different H/E cuts (CMSSW_1_3_1_hlt4) • HLT photon bits with H/E cut: HLT1Photon HLT2Photon
Next Steps • Production: • CMSSW_1_3_1_hlt5 • Produce gamma+jet and QCD backgrounds with generator preselection (working on filter now) • Working on gamma+jets and 2gamma+jets Alpgen samples with Delhi Univ (S. Bhattacharia) • Analysis: • Energy correction • Try to reproduce results from PTDR • CSA07: • Diphoton skim for CSA07 implemented, as part of QCDAnalysis package