• • cvs co -r V00-04-02-16 RecoMET/Configuration

Instructions and Example Use ( How to run it...)

• After building, to see how to incorporate tcMet correction to your analysis sequence, see example in test file. This example will produce a tcMET collection.

• The implementation of tcMET makes use of the metMuonCorrections module that is part of 22X releases. As a result, the user must include the cff file in their cfg (as is done in the above example) and place the module in their path before tcMet as shown below.

Instructions and Example Use

• The following tags are available for using tcMET in 22X releases. After setting up a 22X release area, one should check out
  • cvs co -r V02-05-00-20 RecoMET/METAlgorithms
  • cvs co -r V02-08-02-16 RecoMET/METProducers
  • cvs co -r V00-04-02-15 RecoMET/Configuration
  • cvs co -r V00-06-02-09 DataFormats/METReco

• After building, to see how to incroporate tcMet correction to your analysis sequence, see example in test file.

• The implementation of tcMET makes use of the metMuonCorrections module that is part of 22X releases. As a result, the user must include the cff file in their cfg (as in done in the above example) and place the module in their path before tcMet as shown below.

# load muon corrections for !MET module
process.load("JetMETCorrections.Type1MET.MetMuonCorrections_cff")

# load track-corrected MET module
process.load("RecoMET.METProducers.TCMET_cfi")

# run sequence of muon+track MET corrections
process.p = cms.Path(process.MetMuonCorrections*process.tcMet)

* the configuration files for the modules are

• • JetMETCorrections/Type1MET/python/corMetMuons_cfi.py
  • JetMETCorrections/Type1MET/python/MetMuonCorrectiosn_cff.py
  • RecoMET/METProducers/python/TCMET_cfi.py

It is recommended to use the configurations provided.

• After running a test job, you should see a tcMet collection in your TBrowser

• The tcMet collection can be accessed in the usual way:

Handle< View<MET> > tcmet_h;
    
iEvent.getByLabel("tcMet", tcmet_h);
  
*evt_tcmet        = (tcmet_h->front()).et();
*evt_tcmetPhi     = (tcmet_h->front()).phi();
*evt_tcsumet      = (tcmet_h->front()).sumEt();

• DY events looking for fake MET rejection
• WW events for real MET performance

• ~x3 rejection of fake MET for a cut at 30GeV (similar to 1.6.x performance)
• ~20% improvement of MET resolution in events with real MET (again similar to 1.6.x)
• ~20% improvement in the determination of the direction of the MET as well.

Instructions and Example Use

• Private tags are available for using tcMET in 22X releases. After setting up a 22X release area, one should check out
  • cvs co -r V02-05-00-20 RecoMET/METAlgorithms
  • cvs co -r V02-08-02-16 RecoMET/METProducers
  • cvs co -r V00-04-02-15 RecoMET/Configuration
  • cvs co -r V00-06-02-09 DataFormats/METReco

• After building, running the test file will produce a tcMET collection

• The implementation of tcMET makes use of the metMuonCorrections module that is part of 22X releases. As a result, the user must include the cff file in their cfg and place the module in their path before tcMet as shown below

# load muon corrections for !MET module
process.load("JetMETCorrections.Type1MET.MetMuonCorrections_cff")

# load track-corrected MET module
process.load("RecoMET.METProducers.TCMET_cfi")

# run sequence of muon+track MET corrections
process.p = cms.Path(process.MetMuonCorrections*process.tcMet)

* the configuration files for the modules are

• • JetMETCorrections/Type1MET/python/corMetMuons_cfi.py
  • JetMETCorrections/Type1MET/python/MetMuonCorrectiosn_cff.py
  • RecoMET/METProducers/python/TCMET_cfi.py

It is recommended to use the configurations provided.

• After running a test job, you should see a tcMet collection in your TBrowser

• The tcMet collection can be accessed in the usual way:

Handle< View<MET> > tcmet_h;
    
iEvent.getByLabel("tcMet", tcmet_h);
  
*evt_tcmet        = (tcmet_h->front()).et();
*evt_tcmetPhi     = (tcmet_h->front()).phi();
*evt_tcsumet      = (tcmet_h->front()).sumEt();

• metMuonCorr is met corrected for muons

• • patMET (met_pat_metCor) is corrected for both muons and Jets

• metMuonCorr is MET corrected for muons using the standard CMS method
• met_pat_metCor is PAT MET, where MET has been corrected for muons and the jet energy scale (JES)

Intro & executive summary

• DY events looking for fake MET rejection
• WW events for real MET performance

• ~x3 rejection of fake MET for a cut at 30GeV (similar to 1.6.x performance)
• ~20% improvement of MET resolution in events with real MET (again similar to 1.6.x)
• ~20% improvement in the determination of the direction of the MET as well.

Results for events with fake MET (DY):

Results for events with real MET (WW):

• below are the same plots as a fraction of the generator MET

Comparison of MET direction

• below are plots of delta phi between corrected MET and generator MET for events with real MET

• in both final states, direction resolution improves by ~20%

• Since patMET is about to be used extensively, we compare to what one get from it, out of the box.
  • patMET is corrected for both muons and Jets

Definitions and notations

• caloMET corrected for muons will serve as the baseline for all comparisons

• for comparison of MET in dilepton events, we require the following:
  • dimuon final state
    • two global muons
    • pt > 20 GeV
    • no additional leptons with pt > 20 GeV
  • dielectron final state
    • two electrons
    • pt > 20 GeV
    • no additional leptons with pt > 20 GeV
• for comparison of MET in dijet events, we require the following:

• we use the standard CMS muon correction scheme. Details: met muon corrections are done using JetMETCorrections/Type1MET/python/metMuonCorrections_cff.py which corrects for global muons that also pass
  • nhits > 5
  • pt > 10 (from global fit), abs(eta) < 2.5
  • qoverp_error < 0.5

Validation, N-1 plots

• tracking has changed considerably between 16X and 22X and thus the quality cuts on tracks must be revisited

• quality cuts in 16X were
  • nhits > 6
  • chi2/ndof < 5
  • abs(d0) < 0.05

• changes between 16X and 22X
  • tracking improved at lower pt
  • changed the way hits are defined
    • can now have more than one hit per layer
  • displaced beamSpot requires correction

• below are new N-1 plots using ZJets sample

• Number of valid hits, N-1 plot
  

• tracking group recommends cut of nhits > 10

• Normalized chi-squared, N-1 plot
  

• Corrected impact parameter, N-1 plot
  

• the new track quality cuts are:
  • nhits > 10
  • chi2/ndof < 4
  • abs(d0corr) < 0.1

Definitions and notations

• for comparison of MET in plots below, we require the following:
  • dimuon final state
    • two global muons
    • pt > 20 GeV
    • no additional leptons with pt > 20 GeV
  • dielectron final state
    • two electrons
    • pt > 20 GeV
    • no additional leptons with pt > 20 GeV

• use the following samples
  • /ZJets-madgraph/Fall08_IDEAL_V9_reco-v2/GEN-SIM-RECO
  • /WW_2l/Summer08_IDEAL_V9_v2/GEN-SIM-RECO

N-1 plots

• tracking has changed considerably between 16X and 22X and thus the quality cuts on tracks must be revisited

• quality cuts in 16X were
  • nhits > 6
  • chi2/ndof < 5
  • abs(d0) < 0.05

• changes between 16X and 22X
  • tracking improved at lower pt
  • changed the way hits are defined
    • can now have more than one hit per layer
  • displaced beamSpot requires correction

• below are new N-1 plots using ZJets sample

• Number of valid hits, N-1 plot
  

• tracking group recommends cut of nhits > 10

• Normalized chi-squared, N-1 plot
  

• Corrected impact parameter, N-1 plot
  

• the new track quality cuts are:
  • nhits > 10
  • chi2/ndof < 4
  • abs(d0corr) < 0.1

Results

• below are plots comparing tcMET and caloMET corrected muons
• caloMET corrected for muons will serve as the baseline for all comparisons
• met muon corrections are done using JetMETCorrections/Type1MET/python/metMuonCorrections_cff.py which corrects for global muons that also pass
  • nhits > 5
  • pt > 10 (from global fit), abs(eta) < 2.5
  • qoverp_error < 0.5
• additionally, for comparison we require either
  • two global muons with pt > 20 GeV and no additional leptons with pt > 20 GeV
  • two electrons with pt > 20 GeV and no additional leptons pt > 20 GeV

• we observe significant reduction of the tail of the MET distribution for di-lepton final states, consistent with that seen previously in release 16X

• table for cut MET > 30 GeV

• table for cut MET > 50 GeV

• below are plots comparing met corrected for muons and tcMET from Summer08 WW sample generated with pythia and forced to two leptons

• WW decaying to two leptons has real MET via neutrinos produced along wtih the leptons thus tcMET should have little effect on the MET distribution for this process as observed above

• table for cut MET > 30 GeV

• table for cut MET > 50 GeV

• so, the MET distribution of WW is unchanged by tcMET - actually, we increase the number of events above our cut by a couple percent

• although our goal is to reduce the tails of fake MET distributions, it is also interesting to look at what effect tcMET has on MET resolution
• below are plots comparing the difference between corrected MET and generator MET for muon corrected MET and tcMET

• in both cases, the mean is shifted closer to 0 and the RMS improves
  • the resolution improves by at least 20% in both final states

• below are the same plots a fraction of the generator MET

Comparison with patMET

• although met corrected for muons is our working baseline for comparison, it is interesting to compare tcMET to what one gets out of the box in the the PAT
  • patMET is muon corrected MET + JES

• table for cut MET > 30 GeV

• table for cut MET > 50 GeV

• patMET performs better than muon corrected MET in the muon final state, but worse in the electron final state
  • this result is in agreement with what we saw for muon+!JES corrections to MET in 16X
• tcMET significantly reduces the tail of the MET distribution relative to both types of MET

Comparison of MET direction

• below are plots of delta phi between corrected MET and generator MET for WW in the dimuon final state

• in both final states, direction resolution improves by ~20%

-- FrankGolf - 19 Feb 2009