Lepton Identification

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A lepton identification package called LICH based on Multivariate Data Analysis (TMVA) has been developed for detectors using high granularity calorimeters. Using the conceptual detector geometry for the Circular Electron-Positron Collider (CEPC) and single charged particle samples with energy larger than 2 GeV, LICH identifies electrons/muons with efficiencies higher than 99.5% and controls the mis-identification rate of hadron to muons/electrons to better than 1%/0.5%. Applying on the isolate lepton events, the recoil mass analysis of $eeH$ and $\mu\mu H$ channel, the lepton identification efficiency and purity is around 95% and 97%, which means the isolate leptons performance is comparable to the single particles. Compared to the leptons generated at parton level, performance for the leptons in jet degrades about 1%.

###Process for LICH

 <processor name="MyLICH" type="LICH">
 <!--Produce single particle samples for training or produce the charged PID-->
  <!--energy bins to make cut different-->
  <parameter name="EnergyBins" type="FloatVec">-1  </parameter>
  <parameter name="InputDetectorModules" type="StringVec">barrel1 barrel2 overlap endcap  </parameter>
  <!--Name of Inpout MC Particle Collection-->
  <parameter name="InputMCParticle" type="string">MCParticle </parameter>
  <!--Name of Inpout Reconstructed Particle Collection-->
  <parameter name="InputPFO" type="string">AncientPFOs </parameter>
  <!--The interval of angle for PID-->
  <parameter name="InputPositions" type="FloatVec">0 0.3 0.6 0.8 1  </parameter>
  <!--Name of Output Reconstructed Particle Collection-->
  <parameter name="OutputPFO" type="string">ArborPFOs </parameter>
  <!--Produce sample for training when 0, otherwise proceed the PID-->
  <parameter name="TrainingFlag" type="int">0 </parameter>
  <!--verbosity level of this processor ("DEBUG0-4,MESSAGE0-4,WARNING0-4,ERROR0-4,SILENT")-->
  <!--parameter name="Verbosity" type="string">DEBUG </parameter-->
  <!--mva value cut for electron-->
  <parameter name="mvacut_e" type="FloatVec">0.33  </parameter>
  <!--mva value cut for electron-->
  <parameter name="mvacut_mu" type="FloatVec">0.34  </parameter>
  <!--mva value cut for electron-->
  <parameter name="mvacut_pi" type="FloatVec">0.33  </parameter>
  <!--the weight file directory-->
  <parameter name="weightDir" type="string">/cefs/higgs/yudan/CEPCV4/Reco_Phismear/TMVA </parameter>


   <processor name="MyLICH"/>


Taking event as an sample, the lepton identification efficiency and the mis-id rate for pions to be mis-identified as leptons is shown here. Samples can be found at /cefs/higgs/yudan/LeptonID/Zpole_bb

Eff_Compare Misid_Compare