• Cross section of 13 TeV samples (Note that you need to use the effective XS, i.e. the product of XS and filter efficiency)

• References for cross sections
  • https://twiki.cern.ch/twiki/bin/viewauth/CMS/SummaryTable1G25ns
  • https://twiki.cern.ch/twiki/bin/viewauth/CMS/StandardModelCrossSectionsat13TeV
  • McM https://cms-pdmv.cern.ch/mcm/

• the definition of variables in ggNtuple here

• Which pythia version is used in a given CMSSW ?
  • scram tool list | grep -i pythia

• Official EGM tag-and-probe twiki : here

• How to access muon type in ggNtuple
  • In ggNtuple, the name of the array that stores the muon type is "muType".
    • global muon: muType[] = 1 ; ((muType[] >> 1) &1) = 1 -> global muon
    • tracker muon: muType[] = 2 ; ((muType[] >> 2) &1) = 1 -> tracker muon
    • PF muon: muType[] = 5 ; ((muType[] >> 5) &1) = 1 -> PF muon
• How to remove double counted Z+gamma from Z+jets samples
  • When you select photon in a Z+jet sample, you need to check the mc truth of the reco photon. If reco photon match (has dR < 0.1) to any prompt photon, then we should remove that photon from the selection candidates, since the prompt photon is already in Z+gamma samples.
  • The prompt photon means: mcPID[] == 22 && (mcStatusFlag[]>>1&1)==1.
• How to use mcStatusFlag to identify MC particles
  • The meaning of the bits of mcStatusFlag[] is on this website: "https://github.com/cmkuo/ggAnalysis"
  • isPromptFinalState means the particle is not from underlying process.
  • fromHardProcessBeforeFSR means the particle doesn't suffer from FSR.

• Photon preselections :
  • Hγγ preselection
    • |sc_η| < 2.5 && 1.4442 <|sc_η|< 1.566
    • phoR9Full5x5 > 0.8 || phoPFChIso < 20 || phoPFChIso/pT(γ) < 0.3
    • H/E < 0.08
  • for MVA template method
    • EB : H/E < 0.08, SigmaIEtaIEta (full5x5) < 0.012
    • EE : H/E < 0.05, SigmaIEtaIEta (full5x5) < 0.035
    • All : electron veto, PF photon isolation < 20, Worst PF charged hadron isolation < 20

• In aMC@NLO datasets, there are events negative weight. How to compute the event (MC) weight ? here

• PU reweighting here
  • PU difference between silver (blue) and golden (red) JSON pu_golden_silver.pdf

pileupCalc.py -i MyAnalysisJSON.txt --inputLumiJSON pileup_latest.txt  --calcMode true --minBiasXsec 69000 --maxPileupBin 200 --numPileupBins 1000  MyDataPileupHistogram.root

• How to obtain luminosity ? here

• Example code for making plots in CMS style: /afs/cern.ch/user/l/lgray/work/public/xEGM

-- ChiaMingKuo - 2015-11-18