ElectronSqPtTkIsolation.cc

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//C++ includes
#include <vector>
#include <functional>

//ROOT includes
#include <Math/VectorUtil.h>

//CMSSW includes
#include "Calibration/Tools/plugins/ElectronSqPtTkIsolation.h"
#include "DataFormats/TrackReco/interface/TrackFwd.h"
#include "TrackingTools/PatternTools/interface/Trajectory.h"
#include "TrackingTools/TrajectoryState/interface/TrajectoryStateTransform.h"
#include "DataFormats/GeometryVector/interface/GlobalPoint.h"
#include "DataFormats/GeometryVector/interface/GlobalVector.h"
#include "DataFormats/GsfTrackReco/interface/GsfTrack.h"

using namespace ROOT::Math::VectorUtil;

ElectronSqPtTkIsolation::ElectronSqPtTkIsolation(
    double extRadius, double intRadius, double ptLow, double lip, const reco::TrackCollection* trackCollection)
    : extRadius_(extRadius), intRadius_(intRadius), ptLow_(ptLow), lip_(lip), trackCollection_(trackCollection) {}

ElectronSqPtTkIsolation::~ElectronSqPtTkIsolation() {}

// unified acces to isolations
std::pair<int, double> ElectronSqPtTkIsolation::getIso(const reco::GsfElectron* electron) const {
  int counter = 0;
  double ptSum = 0.;
  //Take the electron track
  reco::GsfTrackRef tmpTrack = electron->gsfTrack();
  math::XYZVector tmpElectronMomentumAtVtx = (*tmpTrack).momentum();

  for (reco::TrackCollection::const_iterator itrTr = (*trackCollection_).begin(); itrTr != (*trackCollection_).end();
       ++itrTr) {
    math::XYZVector tmpTrackMomentumAtVtx = (*itrTr).momentum();
    double this_pt = (*itrTr).pt();
    if (this_pt < ptLow_)
      continue;
    if (fabs((*itrTr).dz() - (*tmpTrack).dz()) > lip_)
      continue;
    double dr = DeltaR(tmpTrackMomentumAtVtx, tmpElectronMomentumAtVtx);
    if (fabs(dr) < extRadius_ && fabs(dr) >= intRadius_) {
      ++counter;
      ptSum += this_pt * this_pt;  // sum of squared pT
    }
  }  //end loop over tracks

  std::pair<int, double> retval;
  retval.first = counter;
  retval.second = ptSum;

  return retval;
}

int ElectronSqPtTkIsolation::getNumberTracks(const reco::GsfElectron* electron) const {
  //counter for the tracks in the isolation cone
  return getIso(electron).first;
}

double ElectronSqPtTkIsolation::getPtTracks(const reco::GsfElectron* electron) const { return getIso(electron).second; }