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High energy photon pairs: L1/HLT Studies

Vladimir Litvin, Toyoko OrimotoCaltech, CMS

QCD Meeting19 June 2007

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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)

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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

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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

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Invariant Masses

1443.0 ± 0.326.6 ± 0.3

720.5 ± 0.115.0 ± 0.2

960.5 ± 0.219.9 ± 0.2

Still need energy correction

Candidates reconstructed from two Island Basic Clusters from ECAL Barrel/Endcap with pt>(30) 100 GeV

born box

750 1000 1500

Pt_photons > 30Pt_photons > 100

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L1 Egamma Efficiencies

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L1 Egamma Efficiencies

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L1 Egamma Efficiencies

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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

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HLT Egamma Efficiencies

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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

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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

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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

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Backup Slides

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L1 Combined Egamma Efficiencies

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L1 Combined Egamma Efficiencies

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L1 Combined Egamma Efficiencies