τ + lepton HLT development

Rate calculation

Rates are calculated using the openHLT framework. Various versions of the code were used to calculate the rates below which leads to variations in the results. The important part is here.

1e33 and 2e33 preliminary rates

Using ntuples from 2010 data for these because of some issues with ntuples produced with 2011 data. Run 149181 with 11/03 production

1e33

Numbers with Josh's modification to HLT_FULL_cfg.py

These rates were calculated using ntuples produced with openHLT according to the recipe for CMSSW 311X. This corresponds to branch V03-06-08 with a modified HLT_FULL_cff.py file.

2e33

Pile-up

The effect of pile-up is considered by running over samples, in this case QCD, that are generated with and without pile-up, and then taking the ratio of the number of events passing for a given trigger in one sample to the other. The errors that I include assume Poisson statistics and the initial number of events is the same for both samples and is about 2E6. The version of the code used is revision 1.237 of OHltTreeOpen.cpp. I use the following ntuples,

   Pile-up
   /castor/cern.ch/user/a/alebihan/openHLT_QCD_Pt-15_TuneZ2_8TeV-pythia6_Winter10-TSG_PU_E8TeV_AVE_10_BX_50ns-v1_cmssw3111_fnal_newPixelSeedingHLT/
   No Pile-up
   /castor/cern.ch/user/a/alebihan/openHLT_QCD_Pt-15_TuneZ2_8TeV-pythia6_Spring11-START39_V6-v1_cmssw3111_ciemat_newPixelSeedingHLT/

Electrons

Muons

Older numbers from ntuples with track bug.   Hide it  

   dcap://cmsdca.fnal.gov:24136/pnfs/fnal.gov/usr/cms/WAX/resilient/lucieg/Commish2010/QCD_Pt-15_TuneZ2_TSG_PU_E8TeV_Feb2011_3111/
   dcap://cmsdca.fnal.gov:24136/pnfs/fnal.gov/usr/cms/WAX/resilient/lucieg/Commish2010/QCD_Pt-15_TuneZ2_TSG_NoPU_E8TeV_Feb2011_3111/

Δd_z

To reduce the effects of PU, we make an association between the trigger objects based on there separation in z (d_z). The association can be made by examining whether the objects associate to a common vertex,

or we can associate between the tau and leptons directly,

τ - e

Based on an exchange with several collaborators, it turns out that we previously were not in conformity with eGamma POG's conventions of naming or the value of the ID/Iso parameters that we were using. Furthermore, we are not in line with what is used online. In the table below is the correct names with the rates calculated using the parameters from this twiki

  dccp: /pnfs/cms/WAX/resilient/lucieg/Commish2010/r149181__Electron_Run2010B-v1__20110311_0614/*

Older numbers from ntuples with track bug.   Hide it  

τ - μ

Current rates

Rates using revision 1.237 of OHltTreeOpen and the following ntuples

  dccp: /pnfs/cms/WAX/resilient/lucieg/Commish2010/r149181__Mu_Run2010B-v1__20110311_0614/*

Older numbers from ntuples with track bug.   Hide it  

Comparison of isolation schemes

Below is a comparison of rates for the OpenHLT_Mu11_PFIsoTau15 while varying the τ seed track p_T and the isolation track p_T threshold. First, I present the rates for the trigger with the original isolation scheme which relied on only using the number of tracks in the isolation region. For the numbers quoted below the requirement is that there be no track in the isolation annulus.

Trigger Rates [Hz] : 
         Name                       Prescale                   Indiv.                Pure   Cumulative
--------------------------------------------------------------------------------------------------
                           HLT_Mu11_PFTau15_v1 (       1)  26.970 +-   0.068    26.970    26.970
                           OpenHLT_Mu11_PFIsoTau15 (       1)    24.528 +-   0.064     8.317     35.286

                                               TOTAL RATE : 35.286 +- 0.077 Hz
--------------------------------------------------------------------------------------------------

For comparison, here is the comparison with the isolation being defined by the p_T of the track or photon in the isolation region, but with the same thresholds.

Trigger Rates [Hz] : 
         Name                       Prescale           Indiv.          Pure   Cumulative
----------------------------------------------------------------------------------------------
             HLT_Mu11_PFTau15_v1 (       1)  22.144 +-   0.108    22.144    22.144
             OpenHLT_Mu11_PFIsoTau15_Trk1_IsoTrk15 (       1)    20.048 +-   0.102     6.707     28.851

                                               TOTAL RATE : 28.851 +- 0.123 Hz
----------------------------------------------------------------------------------------------

Scan of lead and isolation track p_T

A scan was conducted with track p_T isolation threshold taken to be 0.5, 1.0, 1.5 GeV. The lead track p_T was also varied with values 1.0, 4.0, & 7.0 GeV for each individual isolation cut. The threshold on the E_T of the tau was lowered to 10 GeV while the isolation of the photon was held at 1.5 GeV. The result is below.

--------------------------------------------------------------------------------------------------------------------------------------
                               HLT_Mu11_PFTau15_v1 (       1)    22.144 +-   0.108    22.144    22.144
             OpenHLT_Mu11_PFIsoTau10_Trk1_IsoTrk0.5 (       1)    27.307 +-   0.120    14.986    37.130
             OpenHLT_Mu11_PFIsoTau10_Trk1_IsoTrk1.0 (       1)    28.465 +-   0.122     0.319    37.449
             OpenHLT_Mu11_PFIsoTau10_Trk1_IsoTrk1.5 (       1)    31.621 +-   0.129     0.846    38.296
             OpenHLT_Mu11_PFIsoTau10_Trk4_IsoTrk0.5 (       1)    23.135 +-   0.110     0.000    38.296
             OpenHLT_Mu11_PFIsoTau10_Trk4_IsoTrk1.0 (       1)    24.215 +-   0.113     0.000    38.296
             OpenHLT_Mu11_PFIsoTau10_Trk4_IsoTrk1.5 (       1)    27.210 +-   0.119     0.000    38.296
             OpenHLT_Mu11_PFIsoTau10_Trk7_IsoTrk0.5 (       1)    16.062 +-   0.092     0.000    38.296
             OpenHLT_Mu11_PFIsoTau10_Trk7_IsoTrk1.0 (       1)    16.869 +-   0.094     0.000    38.296
             OpenHLT_Mu11_PFIsoTau10_Trk7_IsoTrk1.5 (       1)    19.073 +-   0.100     0.000    38.296
--------------------------------------------------------------------------------------------------------------------------------------

The ntuples were created using /Mu/Run2010B-v1/RAW and run 149181 with lumi section {[229, ], [ , 1290]}. The veto threshold for photons in the isolation annulus is 1.5 GeV. N.B.: For some reason, I have ~10⁶ more events than the existing ntuple from this dataset.

Muon isolation

If we also isolate the muon,

--------------------------------------------------------------------------------------------------------------------------------------
           OpenHLT_IsoMu11_PFIsoTau10_Trk1_IsoTrk1 (       1)     7.688 +-   0.063     5.385    27.529
           OpenHLT_IsoMu11_PFIsoTau10_Trk4_IsoTrk1 (       1)     6.648 +-   0.059     0.000    27.529
--------------------------------------------------------------------------------------------------------------------------------------

If instead of isolating the muon we instead make the η restriction of the muon tighter, the rate can be reduced less dramatically. For reference, the rates with |η|<2.5 are,

--------------------------------------------------------------------------------------------------------------------------------------
             OpenHLT_Mu11_PFIsoTau10_Trk1_IsoTrk1.0 (       1)    28.465 +-   0.122    15.305    37.449
             OpenHLT_Mu11_PFIsoTau10_Trk4_IsoTrk1.0 (       1)    24.215 +-   0.113     0.000    37.449
--------------------------------------------------------------------------------------------------------------------------------------

If we reduce the |&eta| threshold of the muon to 2.1

--------------------------------------------------------------------------------------------------------------------------------------
             OpenHLT_Mu11_PFIsoTau10_Trk1_IsoTrk1.0 (       1)    23.684 +-   0.111    12.162    34.306
             OpenHLT_Mu11_PFIsoTau10_Trk4_IsoTrk1.0 (       1)    20.025 +-   0.102     0.000    34.306
--------------------------------------------------------------------------------------------------------------------------------------

Decreasing this further to |η|<1.5,

--------------------------------------------------------------------------------------------------------------------------------------
             OpenHLT_Mu11_PFIsoTau10_Trk1_IsoTrk1.0 (       1)    22.158 +-   0.108    11.689    33.833
             OpenHLT_Mu11_PFIsoTau10_Trk4_IsoTrk1.0 (       1)    18.821 +-   0.099     0.000    33.833
--------------------------------------------------------------------------------------------------------------------------------------

Comparison of Aruna's and my rates

Electrons

Muons

-- NateOdell - 09-Jan-2011