ZCounting.cc

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#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Common/interface/TriggerNames.h"
#include "FWCore/Utilities/interface/RegexMatch.h"
#include "DataFormats/Common/interface/Handle.h"
#include "DataFormats/Common/interface/TriggerResults.h"
#include "DataFormats/HLTReco/interface/TriggerEvent.h"
#include "DataFormats/VertexReco/interface/Vertex.h"
#include "DataFormats/MuonReco/interface/Muon.h"
#include "DataFormats/MuonReco/interface/MuonSelectors.h"

#include "DQMOffline/Lumi/interface/TriggerDefs.h"
#include "DQMOffline/Lumi/interface/TTrigger.h"
#include "DQMOffline/Lumi/interface/TriggerTools.h"

#include <TLorentzVector.h>

#include "DQMOffline/Lumi/plugins/ZCounting.h"

using namespace ZCountingTrigger;

//
// -------------------------------------- Constructor --------------------------------------------
//
ZCounting::ZCounting(const edm::ParameterSet& iConfig):
  fHLTObjTag         (iConfig.getParameter<edm::InputTag>("TriggerEvent")),
  fHLTTag            (iConfig.getParameter<edm::InputTag>("TriggerResults")),
  fPVName            (iConfig.getUntrackedParameter<std::string>("edmPVName","offlinePrimaryVertices")),
  fMuonName          (iConfig.getUntrackedParameter<std::string>("edmName","muons")),
  fTrackName         (iConfig.getUntrackedParameter<std::string>("edmTrackName","generalTracks")),

  // Electron-specific Parameters
  fElectronName( iConfig.getUntrackedParameter<std::string>("edmGsfEleName","gedGsfElectrons")),
  fSCName( iConfig.getUntrackedParameter<std::string>("edmSCName","particleFlowEGamma")),

  // Electron-specific Tags
  fRhoTag( iConfig.getParameter<edm::InputTag>("rhoname") ),
  fBeamspotTag(iConfig.getParameter<edm::InputTag>("beamspotName") ),
  fConversionTag( iConfig.getParameter<edm::InputTag>("conversionsName")),

  // Electron-specific Cuts
  ELE_PT_CUT_TAG(iConfig.getUntrackedParameter<double>("PtCutEleTag")),
  ELE_PT_CUT_PROBE(iConfig.getUntrackedParameter<double>("PtCutEleProbe")),
  ELE_ETA_CUT_TAG(iConfig.getUntrackedParameter<double>("EtaCutEleTag")),
  ELE_ETA_CUT_PROBE(iConfig.getUntrackedParameter<double>("EtaCutEleProbe")),

  ELE_MASS_CUT_LOW(iConfig.getUntrackedParameter<double>("MassCutEleLow")),
  ELE_MASS_CUT_HIGH(iConfig.getUntrackedParameter<double>("MassCutEleHigh")),

  ELE_ID_WP( iConfig.getUntrackedParameter<std::string>("ElectronIDType","TIGHT")),
  EleID_(ElectronIdentifier(iConfig))
{
  edm::LogInfo("ZCounting") <<  "Constructor  ZCounting::ZCounting " << std::endl;
  
  //Get parameters from configuration file
  fHLTTag_token    = consumes<edm::TriggerResults>(fHLTTag);
  fHLTObjTag_token = consumes<trigger::TriggerEvent>(fHLTObjTag);
  fPVName_token    = consumes<reco::VertexCollection>(fPVName);
  fMuonName_token  = consumes<reco::MuonCollection>(fMuonName);
  fTrackName_token = consumes<reco::TrackCollection>(fTrackName);

  // Electron-specific parameters
  fGsfElectronName_token  = consumes<edm::View<reco::GsfElectron>>(fElectronName);
  fSCName_token           = consumes<edm::View<reco::SuperCluster>>(fSCName);
  fRhoToken               = consumes<double>(fRhoTag);
  fBeamspotToken          = consumes<reco::BeamSpot>(fBeamspotTag);
  fConversionToken        = consumes<reco::ConversionCollection>(fConversionTag);

  // Muon-specific Cuts
  IDTypestr_       = iConfig.getUntrackedParameter<std::string>("IDType");
  IsoTypestr_      = iConfig.getUntrackedParameter<std::string>("IsoType");
  IsoCut_          = iConfig.getUntrackedParameter<double>("IsoCut");

  if     (IDTypestr_ == "Loose")  IDType_ = LooseID;
  else if(IDTypestr_ == "Medium") IDType_ = MediumID;
  else if(IDTypestr_ == "Tight")  IDType_ = TightID;
  else                            IDType_ = NoneID;

  if     (IsoTypestr_ == "Tracker-based") IsoType_ = TrackerIso; 
  else if(IsoTypestr_ == "PF-based")      IsoType_ = PFIso;
  else                                    IsoType_ = NoneIso;

  PtCutL1_  = iConfig.getUntrackedParameter<double>("PtCutL1");
  PtCutL2_  = iConfig.getUntrackedParameter<double>("PtCutL2");
  EtaCutL1_ = iConfig.getUntrackedParameter<double>("EtaCutL1");
  EtaCutL2_ = iConfig.getUntrackedParameter<double>("EtaCutL2");

  MassBin_  = iConfig.getUntrackedParameter<int>("MassBin");
  MassMin_  = iConfig.getUntrackedParameter<double>("MassMin");
  MassMax_  = iConfig.getUntrackedParameter<double>("MassMax");

  LumiBin_  = iConfig.getUntrackedParameter<int>("LumiBin");
  LumiMin_  = iConfig.getUntrackedParameter<double>("LumiMin");
  LumiMax_  = iConfig.getUntrackedParameter<double>("LumiMax");

  PVBin_    = iConfig.getUntrackedParameter<int>("PVBin");
  PVMin_    = iConfig.getUntrackedParameter<double>("PVMin");
  PVMax_    = iConfig.getUntrackedParameter<double>("PVMax");

  VtxNTracksFitCut_ = iConfig.getUntrackedParameter<double>("VtxNTracksFitMin");
  VtxNdofCut_       = iConfig.getUntrackedParameter<double>("VtxNdofMin");
  VtxAbsZCut_       = iConfig.getUntrackedParameter<double>("VtxAbsZMax");
  VtxRhoCut_        = iConfig.getUntrackedParameter<double>("VtxRhoMax");

  EleID_.setID(ELE_ID_WP);
}

//
//  -------------------------------------- Destructor --------------------------------------------
//
ZCounting::~ZCounting()
{
  edm::LogInfo("ZCounting") <<  "Destructor ZCounting::~ZCounting " << std::endl;
}

//
// -------------------------------------- beginRun --------------------------------------------
//
void ZCounting::dqmBeginRun(edm::Run const &, edm::EventSetup const &)
{
  edm::LogInfo("ZCounting") <<  "ZCounting::beginRun" << std::endl;

  // Triggers
  fTrigger.reset(new ZCountingTrigger::TTrigger());
  
}
//
// -------------------------------------- bookHistos --------------------------------------------
//
void ZCounting::bookHistograms(DQMStore::IBooker & ibooker_, edm::Run const &, edm::EventSetup const &)
{
  edm::LogInfo("ZCounting") <<  "ZCounting::bookHistograms" << std::endl;

  ibooker_.cd();
  ibooker_.setCurrentFolder("ZCounting/Histograms");


  // Muon histograms
  h_mass_HLT_pass_central = ibooker_.book2D("h_mass_HLT_pass_central", "h_mass_HLT_pass_central", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_mass_HLT_pass_forward = ibooker_.book2D("h_mass_HLT_pass_forward", "h_mass_HLT_pass_forward", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_mass_HLT_fail_central = ibooker_.book2D("h_mass_HLT_fail_central", "h_mass_HLT_fail_central", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_mass_HLT_fail_forward = ibooker_.book2D("h_mass_HLT_fail_forward", "h_mass_HLT_fail_forward", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);

  h_mass_SIT_pass_central = ibooker_.book2D("h_mass_SIT_pass_central", "h_mass_SIT_pass_central", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_mass_SIT_pass_forward = ibooker_.book2D("h_mass_SIT_pass_forward", "h_mass_SIT_pass_forward", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_mass_SIT_fail_central = ibooker_.book2D("h_mass_SIT_fail_central", "h_mass_SIT_fail_central", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_mass_SIT_fail_forward = ibooker_.book2D("h_mass_SIT_fail_forward", "h_mass_SIT_fail_forward", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);

  h_mass_Sta_pass_central = ibooker_.book2D("h_mass_Sta_pass_central", "h_mass_Sta_pass_central", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_mass_Sta_pass_forward = ibooker_.book2D("h_mass_Sta_pass_forward", "h_mass_Sta_pass_forward", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_mass_Sta_fail_central = ibooker_.book2D("h_mass_Sta_fail_central", "h_mass_Sta_fail_central", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_mass_Sta_fail_forward = ibooker_.book2D("h_mass_Sta_fail_forward", "h_mass_Sta_fail_forward", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);

  h_npv                   = ibooker_.book2D("h_npv",     "h_npv",     LumiBin_, LumiMin_, LumiMax_, PVBin_, PVMin_, PVMax_);
  h_yield_Z               = ibooker_.book1D("h_yield_Z", "h_yield_Z", LumiBin_, LumiMin_, LumiMax_);
  h_yieldBB_Z             = ibooker_.book1D("h_yieldBB_Z", "h_yieldBB_Z", LumiBin_, LumiMin_, LumiMax_);
  h_yieldEE_Z             = ibooker_.book1D("h_yieldEE_Z", "h_yieldEE_Z", LumiBin_, LumiMin_, LumiMax_);


  // Electron histograms
  h_ee_mass_id_pass_central  = ibooker_.book2D("h_ee_mass_id_pass_central", "h_ee_mass_id_pass_central", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_ee_mass_id_fail_central  = ibooker_.book2D("h_ee_mass_id_fail_central", "h_ee_mass_id_fail_central", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_ee_mass_id_pass_forward  = ibooker_.book2D("h_ee_mass_id_pass_forward", "h_ee_mass_id_pass_forward", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_ee_mass_id_fail_forward  = ibooker_.book2D("h_ee_mass_id_fail_forward", "h_ee_mass_id_fail_forward", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);

  h_ee_mass_HLT_pass_central = ibooker_.book2D("h_ee_mass_HLT_pass_central", "h_ee_mass_HLT_pass_central", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_ee_mass_HLT_fail_central = ibooker_.book2D("h_ee_mass_HLT_fail_central", "h_ee_mass_HLT_fail_central", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_ee_mass_HLT_pass_forward = ibooker_.book2D("h_ee_mass_HLT_pass_forward", "h_ee_mass_HLT_pass_forward", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);
  h_ee_mass_HLT_fail_forward = ibooker_.book2D("h_ee_mass_HLT_fail_forward", "h_ee_mass_HLT_fail_forward", LumiBin_, LumiMin_, LumiMax_, MassBin_, MassMin_, MassMax_);

  h_ee_yield_Z_ebeb       = ibooker_.book1D("h_ee_yield_Z_ebeb", "h_ee_yield_Z_ebeb", LumiBin_, LumiMin_, LumiMax_);
  h_ee_yield_Z_ebee       = ibooker_.book1D("h_ee_yield_Z_ebee", "h_ee_yield_Z_ebee", LumiBin_, LumiMin_, LumiMax_);
  h_ee_yield_Z_eeee       = ibooker_.book1D("h_ee_yield_Z_eeee", "h_ee_yield_Z_eeee", LumiBin_, LumiMin_, LumiMax_);
}

//
// -------------------------------------- Analyze --------------------------------------------
//
//--------------------------------------------------------------------------------------------------
void ZCounting::analyze(const edm::Event& iEvent, const edm::EventSetup& iSetup)
{// Fill event tree on the fly 
  edm::LogInfo("ZCounting") <<  "ZCounting::analyze" << std::endl;
  analyzeMuons(iEvent, iSetup);
  analyzeElectrons(iEvent, iSetup);
}

void ZCounting::analyzeMuons(const edm::Event& iEvent, const edm::EventSetup& iSetup) {
  edm::LogInfo("ZCounting") <<  "ZCounting::analyzeMuons" << std::endl;
  //-------------------------------
  //--- Vertex 
  //-------------------------------
  edm::Handle<reco::VertexCollection> hVertexProduct;
  iEvent.getByToken(fPVName_token,hVertexProduct);
  if(!hVertexProduct.isValid()) return;

  const reco::VertexCollection *pvCol = hVertexProduct.product();
  const reco::Vertex* pv = &(*pvCol->begin());
  int nvtx = 0;
 
  for(auto const & itVtx : *hVertexProduct) {
    if(itVtx.isFake())                             continue;
    if(itVtx.tracksSize()     < VtxNTracksFitCut_) continue;
    if(itVtx.ndof()           < VtxNdofCut_)       continue;
    if(fabs(itVtx.z())        > VtxAbsZCut_)       continue;
    if(itVtx.position().Rho() > VtxRhoCut_)        continue;

    if(nvtx==0) {
      pv = &itVtx;
    }
    nvtx++;
  }

  h_npv->Fill(iEvent.luminosityBlock(), nvtx);

  // Good vertex requirement
  if(nvtx==0) return;

  //-------------------------------
  //--- Trigger 
  //-------------------------------
  edm::Handle<edm::TriggerResults> hTrgRes;
  iEvent.getByToken(fHLTTag_token,hTrgRes);
  if(!hTrgRes.isValid()) return;

  edm::Handle<trigger::TriggerEvent> hTrgEvt;
  iEvent.getByToken(fHLTObjTag_token,hTrgEvt);

  const edm::TriggerNames &triggerNames = iEvent.triggerNames(*hTrgRes);
  bool config_changed = false;
  if(fTriggerNamesID != triggerNames.parameterSetID()) {
    fTriggerNamesID = triggerNames.parameterSetID();
    config_changed  = true;
  }
  if(config_changed) {
    initHLT(*hTrgRes, triggerNames);
  }

  TriggerBits triggerBits;
  for(unsigned int irec=0; irec<fTrigger->fRecords.size(); irec++) {
    if(fTrigger->fRecords[irec].hltPathIndex == (unsigned int)-1) continue;
    if(hTrgRes->accept(fTrigger->fRecords[irec].hltPathIndex)) {
      triggerBits [fTrigger->fRecords[irec].baconTrigBit] = true;
    }
  }
  //if(fSkipOnHLTFail && triggerBits == 0) return;

  // Trigger requirement
  if(!isMuonTrigger(*fTrigger, triggerBits)) return;

  //-------------------------------
  //--- Muons and Tracks 
  //-------------------------------
  edm::Handle<reco::MuonCollection> hMuonProduct;
  iEvent.getByToken(fMuonName_token,hMuonProduct);
  if(!hMuonProduct.isValid()) return;

  edm::Handle<reco::TrackCollection> hTrackProduct;
  iEvent.getByToken(fTrackName_token,hTrackProduct);
  if(!hTrackProduct.isValid()) return;

  TLorentzVector vTag(0.,0.,0.,0.);
  TLorentzVector vProbe(0.,0.,0.,0.);
  TLorentzVector vTrack(0.,0.,0.,0.);

  // Tag loop
  for(auto const & itMu1 : *hMuonProduct) {

    float pt1  = itMu1.muonBestTrack()->pt();
    float eta1 = itMu1.muonBestTrack()->eta();
    float phi1 = itMu1.muonBestTrack()->phi();
    float q1   = itMu1.muonBestTrack()->charge();

    // Tag selection: kinematic cuts, lepton selection and trigger matching
    if(pt1        < PtCutL1_)  continue;
    if(fabs(eta1) > EtaCutL1_) continue;
    if(!(passMuonID(itMu1, *pv, IDType_) && passMuonIso(itMu1, IsoType_, IsoCut_))) continue;
    if(!isMuonTriggerObj(*fTrigger, TriggerTools::matchHLT(eta1, phi1, fTrigger->fRecords, *hTrgEvt))) continue;

    vTag.SetPtEtaPhiM(pt1, eta1, phi1, MUON_MASS);

    // Probe loop over muons
    for(auto const & itMu2 : *hMuonProduct) {
      if(&itMu2 == &itMu1) continue;

      float pt2  = itMu2.muonBestTrack()->pt();
      float eta2 = itMu2.muonBestTrack()->eta();
      float phi2 = itMu2.muonBestTrack()->phi();
      float q2   = itMu2.muonBestTrack()->charge();

      // Probe selection: kinematic cuts and opposite charge requirement
      if(pt2        < PtCutL2_)  continue;
      if(fabs(eta2) > EtaCutL2_) continue;
      if(q1 == q2)               continue;

      vProbe.SetPtEtaPhiM(pt2, eta2, phi2, MUON_MASS);

      // Mass window
      TLorentzVector vDilep = vTag + vProbe;
      float dilepMass = vDilep.M();
      if((dilepMass < MassMin_) || (dilepMass > MassMax_)) continue;

      bool isTagCentral   = false;
      bool isProbeCentral = false;
      if(fabs(eta1) < MUON_BOUND) isTagCentral   = true;
      if(fabs(eta2) < MUON_BOUND) isProbeCentral = true;

      // Determine event category for efficiency calculation
      if(passMuonID(itMu2, *pv, IDType_) && passMuonIso(itMu2, IsoType_, IsoCut_)){
        if(isMuonTriggerObj(*fTrigger, TriggerTools::matchHLT(eta2, phi2, fTrigger->fRecords, *hTrgEvt))){
          // category 2HLT: both muons passing trigger requirements
          if(&itMu1>&itMu2) continue;  // make sure we don't double count MuMu2HLT category

          // Fill twice for each event, since both muons pass trigger 
          if(isTagCentral){
            h_mass_HLT_pass_central->Fill(iEvent.luminosityBlock(), dilepMass);
            h_mass_SIT_pass_central->Fill(iEvent.luminosityBlock(), dilepMass);
            h_mass_Sta_pass_central->Fill(iEvent.luminosityBlock(), dilepMass);
          }
          else
          {
            h_mass_HLT_pass_forward->Fill(iEvent.luminosityBlock(), dilepMass);
            h_mass_SIT_pass_forward->Fill(iEvent.luminosityBlock(), dilepMass);
            h_mass_Sta_pass_forward->Fill(iEvent.luminosityBlock(), dilepMass);
          }

          if(isProbeCentral){
            h_mass_HLT_pass_central->Fill(iEvent.luminosityBlock(), dilepMass);
            h_mass_SIT_pass_central->Fill(iEvent.luminosityBlock(), dilepMass);
            h_mass_Sta_pass_central->Fill(iEvent.luminosityBlock(), dilepMass);
          }
          else
          {
            h_mass_HLT_pass_forward->Fill(iEvent.luminosityBlock(), dilepMass);
            h_mass_SIT_pass_forward->Fill(iEvent.luminosityBlock(), dilepMass);
            h_mass_Sta_pass_forward->Fill(iEvent.luminosityBlock(), dilepMass);
          }

        }
        else{
          // category 1HLT: probe passing selection but not trigger
          if(isProbeCentral){
            h_mass_HLT_fail_central->Fill(iEvent.luminosityBlock(), dilepMass);
            h_mass_SIT_pass_central->Fill(iEvent.luminosityBlock(), dilepMass);
            h_mass_Sta_pass_central->Fill(iEvent.luminosityBlock(), dilepMass);
          }
          else
          {
            h_mass_HLT_fail_forward->Fill(iEvent.luminosityBlock(), dilepMass);
            h_mass_SIT_pass_forward->Fill(iEvent.luminosityBlock(), dilepMass);
            h_mass_Sta_pass_forward->Fill(iEvent.luminosityBlock(), dilepMass);
          }

        }
        // category 2HLT + 1HLT: Fill once for Z yield 
        h_yield_Z->Fill(iEvent.luminosityBlock());
        if(isTagCentral && isProbeCentral) h_yieldBB_Z->Fill(iEvent.luminosityBlock());
    else if(!isTagCentral && !isProbeCentral) h_yieldEE_Z->Fill(iEvent.luminosityBlock());
      }
      else if(itMu2.isGlobalMuon()){
        // category NoSel: probe is a GLB muon but failing selection 
        if(isProbeCentral){
          h_mass_SIT_fail_central->Fill(iEvent.luminosityBlock(), dilepMass);
          h_mass_Sta_pass_central->Fill(iEvent.luminosityBlock(), dilepMass);
        }
        else
        {
          h_mass_SIT_fail_forward->Fill(iEvent.luminosityBlock(), dilepMass);
          h_mass_Sta_pass_forward->Fill(iEvent.luminosityBlock(), dilepMass);
        }
      }
      else if(itMu2.isStandAloneMuon()){
        // category STA: probe is a STA muon
        if(isProbeCentral){
          h_mass_Sta_fail_central->Fill(iEvent.luminosityBlock(), dilepMass);
        }
        else
        {
          h_mass_Sta_fail_forward->Fill(iEvent.luminosityBlock(), dilepMass);
        }
      }
      else if(itMu2.innerTrack()->hitPattern().trackerLayersWithMeasurement() >= 6 && itMu2.innerTrack()->hitPattern().numberOfValidPixelHits() >= 1){
        // cateogry Trk: probe is a tracker track
        if(isProbeCentral){
          h_mass_Sta_fail_central->Fill(iEvent.luminosityBlock(), dilepMass);
        }
        else
        {
          h_mass_Sta_fail_forward->Fill(iEvent.luminosityBlock(), dilepMass);
        }
      }

    }// End of probe loop over muons

    // Probe loop over tracks, only for standalone efficiency calculation
    for(auto const & itTrk : *hTrackProduct) {

      // Check track is not a muon
      bool isMuon = false;
      for(auto const & itMu : *hMuonProduct) {
        if(itMu.innerTrack().isNonnull() && itMu.innerTrack().get() == &itTrk) {
          isMuon = true;
          break;
        }
      }
      if(isMuon) continue;

      float pt2  = itTrk.pt();
      float eta2 = itTrk.eta();
      float phi2 = itTrk.phi();
      float q2   = itTrk.charge();

      // Probe selection:  kinematic cuts and opposite charge requirement
      if(pt2        < PtCutL2_)  continue;
      if(fabs(eta2) > EtaCutL2_) continue;
      if(q1 == q2)               continue;

      vTrack.SetPtEtaPhiM(pt2, eta2, phi2, MUON_MASS);

      TLorentzVector vDilep = vTag + vTrack;
      float dilepMass = vDilep.M();
      if((dilepMass < MassMin_) || (dilepMass > MassMax_)) continue;

      bool isTrackCentral = false;
      if(fabs(eta2) > MUON_BOUND) isTrackCentral = true;

      if(itTrk.hitPattern().trackerLayersWithMeasurement() >= 6 && itTrk.hitPattern().numberOfValidPixelHits() >= 1){
        if(isTrackCentral) h_mass_Sta_fail_central->Fill(iEvent.luminosityBlock(), dilepMass);
        else               h_mass_Sta_fail_forward->Fill(iEvent.luminosityBlock(), dilepMass);
      }

    }//End of probe loop over tracks

  }//End of tag loop

}
void ZCounting::analyzeElectrons(const edm::Event& iEvent, const edm::EventSetup& iSetup) {
  edm::LogInfo("ZCounting") <<  "ZCounting::analyzeElectrons" << std::endl;

  //-------------------------------
  //--- Vertex
  //-------------------------------
  edm::Handle<reco::VertexCollection> hVertexProduct;
  iEvent.getByToken(fPVName_token,hVertexProduct);
  if(!hVertexProduct.isValid()) return;

  const reco::VertexCollection *pvCol = hVertexProduct.product();
  int nvtx = 0;

  for(auto const & vtx : *pvCol) {
    if(vtx.isFake())                             continue;
    if(vtx.tracksSize()     < VtxNTracksFitCut_) continue;
    if(vtx.ndof()           < VtxNdofCut_)       continue;
    if(fabs(vtx.z())        > VtxAbsZCut_)       continue;
    if(vtx.position().Rho() > VtxRhoCut_)        continue;

    nvtx++;
  }

  // Good vertex requirement
  if(nvtx==0) return;

  //-------------------------------
  //--- Trigger
  //-------------------------------
  edm::Handle<edm::TriggerResults> hTrgRes;
  iEvent.getByToken(fHLTTag_token,hTrgRes);
  if(!hTrgRes.isValid()) return;

  edm::Handle<trigger::TriggerEvent> hTrgEvt;
  iEvent.getByToken(fHLTObjTag_token,hTrgEvt);


  const edm::TriggerNames &triggerNames = iEvent.triggerNames(*hTrgRes);
  Bool_t config_changed = false;
  if(fTriggerNamesID != triggerNames.parameterSetID()) {
    fTriggerNamesID = triggerNames.parameterSetID();
    config_changed  = true;
  }
  if(config_changed) {
    initHLT(*hTrgRes, triggerNames);
  }

  TriggerBits triggerBits;
  for(unsigned int irec=0; irec<fTrigger->fRecords.size(); irec++) {
    if(fTrigger->fRecords[irec].hltPathIndex == (unsigned int)-1) continue;
    if(hTrgRes->accept(fTrigger->fRecords[irec].hltPathIndex)) {
      triggerBits [fTrigger->fRecords[irec].baconTrigBit] = true;
    }
  }

  // Trigger requirement
  if(!isElectronTrigger(*fTrigger, triggerBits)) return;

  // Get Electrons
  edm::Handle<edm::View<reco::GsfElectron> > electrons;
  iEvent.getByToken(fGsfElectronName_token, electrons);

  // Get SuperClusters
  edm::Handle<edm::View<reco::SuperCluster> > superclusters;
  iEvent.getByToken(fSCName_token, superclusters);

  // Get Rho
  edm::Handle<double> rhoHandle;
  iEvent.getByToken(fRhoToken, rhoHandle);
  EleID_.setRho(*rhoHandle);

  // Get beamspot
  edm::Handle<reco::BeamSpot> beamspotHandle;
  iEvent.getByToken(fBeamspotToken, beamspotHandle);

  // Conversions
  edm::Handle<reco::ConversionCollection> conversionsHandle;
  iEvent.getByToken(fConversionToken, conversionsHandle);


  edm::Ptr<reco::GsfElectron> eleProbe;
  enum { eEleEle2HLT=1, eEleEle1HLT1L1, eEleEle1HLT, eEleEleNoSel, eEleSC };  // event category enum

  // Loop over Tags
  for (size_t itag = 0; itag < electrons->size(); ++itag){
    const auto el1 = electrons->ptrAt(itag);
    if( not EleID_.passID(el1,beamspotHandle,conversionsHandle) ) continue;

    float pt1  = el1->pt();
    float eta1 = el1->eta();
    float phi1 = el1->phi();

    if(!isElectronTriggerObj(*fTrigger, TriggerTools::matchHLT(eta1, phi1, fTrigger->fRecords, *hTrgEvt))) continue;
    TLorentzVector vTag(0.,0.,0.,0.);
    vTag.SetPtEtaPhiM(pt1, eta1, phi1, ELECTRON_MASS);


    // Tag selection: kinematic cuts, lepton selection and trigger matching
    double tag_pt = vTag.Pt();
    double tag_abseta = fabs(vTag.Eta());

    bool tag_is_valid_tag = ele_tag_selection(tag_pt,tag_abseta);
    bool tag_is_valid_probe = ele_probe_selection(tag_pt,tag_abseta);

    if( not (tag_is_valid_tag or tag_is_valid_probe) ) continue;

    // Loop over probes
    for (size_t iprobe = 0; iprobe < superclusters->size(); ++iprobe){
      // Initialize probe
      const auto sc = superclusters->ptrAt(iprobe);
      if(*sc == *(el1->superCluster())) {
        continue;
      }

      // Find matching electron
      for (size_t iele = 0; iele < electrons->size(); ++iele){
        if(iele == itag) continue;
        const auto ele = electrons->ptrAt(iele);
        if(*sc == *(ele->superCluster())) {
          eleProbe = ele;
          break;
        }
      }

      // Assign final probe 4-vector
      TLorentzVector vProbe(0.,0.,0.,0.);
      if(eleProbe.isNonnull()){
        vProbe.SetPtEtaPhiM( eleProbe->pt(), eleProbe->eta(), eleProbe->phi(), ELECTRON_MASS);
      } else {
        double pt = sc->energy() * sqrt( 1 - pow(tanh(sc->eta()),2) );
        vProbe.SetPtEtaPhiM( pt, sc->eta(), sc->phi(), ELECTRON_MASS);
      }

      // Probe Selection
      double probe_pt = vProbe.Pt();
      double probe_abseta = fabs(sc->eta());
      bool probe_is_valid_probe = ele_probe_selection(probe_pt, probe_abseta);
      if( !probe_is_valid_probe ) continue;

      // Good Probe found!

      // Require good Z
      TLorentzVector vDilep = vTag + vProbe;

      if((vDilep.M()<ELE_MASS_CUT_LOW) || (vDilep.M()>ELE_MASS_CUT_HIGH)) continue;
      if(eleProbe.isNonnull() and (eleProbe->charge() != - el1->charge())) continue;

      // Good Z found!

      long ls = iEvent.luminosityBlock();
      bool probe_pass_trigger = isElectronTriggerObj(*fTrigger, TriggerTools::matchHLT(vProbe.Eta(), vProbe.Phi(), fTrigger->fRecords, *hTrgEvt));
      bool probe_pass_id = eleProbe.isNonnull() and EleID_.passID(eleProbe,beamspotHandle,conversionsHandle);

      bool probe_is_forward = probe_abseta > ELE_ETA_CRACK_LOW;
      bool tag_is_forward = tag_abseta > ELE_ETA_CRACK_LOW;

      if(probe_pass_id) {
        if(probe_is_forward and tag_is_forward) {
          h_ee_yield_Z_eeee -> Fill(ls);
        } else if(!probe_is_forward and !tag_is_forward) {
          h_ee_yield_Z_ebeb -> Fill(ls);
        } else {
          h_ee_yield_Z_ebee -> Fill(ls);
        }
      }

      if(!tag_is_valid_tag) continue;

      if(probe_pass_id) {
        if(probe_is_forward) {
          h_ee_mass_id_pass_forward->Fill(ls, vDilep.M());
        } else {
          h_ee_mass_id_pass_central->Fill(ls, vDilep.M());
        }
      } else {
          if(probe_is_forward) {
            h_ee_mass_id_fail_forward->Fill(ls, vDilep.M());
          } else {
            h_ee_mass_id_fail_central->Fill(ls, vDilep.M());
          }
      }

      if(probe_pass_id and probe_pass_trigger) {
        if(probe_is_forward) {
          h_ee_mass_HLT_pass_forward->Fill(ls, vDilep.M());
        } else {
          h_ee_mass_HLT_pass_central->Fill(ls, vDilep.M());
        }
      } else if (probe_pass_id) {
        if(probe_is_forward) {
          h_ee_mass_HLT_fail_forward->Fill(ls, vDilep.M());
        } else {
          h_ee_mass_HLT_fail_central->Fill(ls, vDilep.M());
        }
      }
    } // End of probe loop
  }//End of tag loop

}

bool ZCounting::ele_probe_selection(double pt, double abseta){
  if(pt < ELE_PT_CUT_PROBE) return false;
  if(abseta > ELE_ETA_CUT_PROBE) return false;
  if( (abseta > ELE_ETA_CRACK_LOW) and (abseta < ELE_ETA_CRACK_HIGH) ) return false;
  return true;
}
bool ZCounting::ele_tag_selection(double pt, double abseta){
  if(pt < ELE_PT_CUT_TAG) return false;
  if(abseta > ELE_ETA_CUT_TAG) return false;
  if( (abseta > ELE_ETA_CRACK_LOW) and (abseta < ELE_ETA_CRACK_HIGH) ) return false;
  return true;
}
//
// -------------------------------------- functions --------------------------------------------
//

void ZCounting::initHLT(const edm::TriggerResults& result, const edm::TriggerNames& triggerNames)
{
  for(unsigned int irec=0; irec<fTrigger->fRecords.size(); irec++) {
    fTrigger->fRecords[irec].hltPathName  = "";
    fTrigger->fRecords[irec].hltPathIndex = (unsigned int)-1;
    const std::string pattern = fTrigger->fRecords[irec].hltPattern;
    if(edm::is_glob(pattern)) {  // handle pattern with wildcards (*,?)
      std::vector<std::vector<std::string>::const_iterator> matches = edm::regexMatch(triggerNames.triggerNames(), pattern);
      if(matches.empty()) {
        edm::LogWarning("ZCounting") << "requested pattern [" << pattern << "] does not match any HLT paths" << std::endl;
      } else {
        for(auto const& match : matches) {
          fTrigger->fRecords[irec].hltPathName = *match;
        }
      }
    } else {  // take full HLT path name given
      fTrigger->fRecords[irec].hltPathName = pattern;
    }
    // Retrieve index in trigger menu corresponding to HLT path
    unsigned int index = triggerNames.triggerIndex(fTrigger->fRecords[irec].hltPathName);
    if(index < result.size()) {  // check for valid index
      fTrigger->fRecords[irec].hltPathIndex = index;
    }
  }
}

//--------------------------------------------------------------------------------------------------
bool ZCounting::isMuonTrigger(const ZCountingTrigger::TTrigger &triggerMenu, const TriggerBits &hltBits)
{
  return triggerMenu.pass("HLT_IsoMu27_v*",hltBits);
}

//--------------------------------------------------------------------------------------------------
bool ZCounting::isMuonTriggerObj(const ZCountingTrigger::TTrigger &triggerMenu, const TriggerObjects &hltMatchBits)
{
  return triggerMenu.passObj("HLT_IsoMu27_v*","hltL3crIsoL1sMu22Or25L1f0L2f10QL3f27QL3trkIsoFiltered0p07",hltMatchBits);
}

//--------------------------------------------------------------------------------------------------
bool ZCounting::passMuonID(const reco::Muon& muon, const reco::Vertex& vtx, const MuonIDTypes &idType)
{//Muon ID selection, using internal function "DataFormats/MuonReco/src/MuonSelectors.cc

  if     (idType == LooseID  && muon::isLooseMuon(muon))      return true;
  else if(idType == MediumID && muon::isMediumMuon(muon))     return true;
  else if(idType == TightID  && muon::isTightMuon(muon, vtx)) return true;
  else if(idType == NoneID)                                   return true;
  else                                                        return false;
}
//--------------------------------------------------------------------------------------------------
bool ZCounting::passMuonIso(const reco::Muon& muon, const MuonIsoTypes &isoType, const float isoCut)
{//Muon isolation selection, up-to-date with MUO POG recommendation

    if(isoType == TrackerIso && muon.isolationR03().sumPt < isoCut) return true;
    else if(isoType == PFIso && muon.pfIsolationR04().sumChargedHadronPt + std::max(0.,muon.pfIsolationR04().sumNeutralHadronEt + muon.pfIsolationR04().sumPhotonEt - 0.5*muon.pfIsolationR04().sumPUPt) < isoCut) return true;
    else if(isoType == NoneIso) return true;
    else                        return false;
}

//--------------------------------------------------------------------------------------------------
bool ZCounting::isElectronTrigger(ZCountingTrigger::TTrigger triggerMenu, TriggerBits hltBits)
{
  return triggerMenu.pass("HLT_Ele35_WPTight_Gsf_v*",hltBits);
}
//--------------------------------------------------------------------------------------------------
bool ZCounting::isElectronTriggerObj(ZCountingTrigger::TTrigger triggerMenu, TriggerObjects hltMatchBits)
{
  return triggerMenu.passObj("HLT_Ele35_WPTight_Gsf_v*","hltEle35noerWPTightGsfTrackIsoFilter",hltMatchBits);
}
DEFINE_FWK_MODULE(ZCounting);