JetVertexMain.cc

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#include "JetMETCorrections/JetVertexAssociation/interface/JetVertexMain.h"
#include "DataFormats/JetReco/interface/CaloJet.h"
#include "DataFormats/TrackReco/interface/Track.h"
#include "DataFormats/TrackReco/interface/TrackFwd.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include <cmath>
#include <string>
using namespace reco;
using namespace edm;

JetVertexMain::JetVertexMain(const ParameterSet& parameters) {
  cutSigmaZ = parameters.getParameter<double>("JV_sigmaZ");
  cutDeltaZ = parameters.getParameter<double>("JV_deltaZ");
  threshold = parameters.getParameter<double>("JV_alpha_threshold");
  cone_size = parameters.getParameter<double>("JV_cone_size");
  Algo = parameters.getParameter<int>("JV_type_Algo");
  cutType = parameters.getParameter<std::string>("JV_cutType");
}

std::pair<double, bool> JetVertexMain::Main(const reco::CaloJet& jet,
                                            edm::Handle<TrackCollection> tracks,
                                            double signal_vert_Z,
                                            double signal_vert_z_error) const {
  std::pair<double, bool> parameter;

  double jet_et = jet.et();
  double jet_phi = jet.phi();
  double jet_eta = jet.eta();

  //  cout<<"JET: "<<jet_et<<endl;
  double Pt_jets_X = 0.;
  double Pt_jets_Y = 0.;
  double Pt_jets_X_tot = 0.;
  double Pt_jets_Y_tot = 0.;

  TrackCollection::const_iterator track = tracks->begin();

  if (!tracks->empty()) {
    for (; track != tracks->end(); track++) {
      double Vertex_Z = track->vz();
      double Vertex_Z_Error = track->dzError();
      double track_eta = track->eta();
      double track_phi = track->phi();

      if (DeltaR(track_eta, jet_eta, track_phi, jet_phi) < cone_size) {
        double DeltaZ = Vertex_Z - signal_vert_Z;
        double DeltaZ_Error = sqrt((Vertex_Z_Error * Vertex_Z_Error) + (signal_vert_z_error * signal_vert_z_error));
        Pt_jets_X_tot += track->px();
        Pt_jets_Y_tot += track->py();
        bool discriminator;
        if (cutType == "sig")
          discriminator = (fabs(DeltaZ) / DeltaZ_Error) <= cutSigmaZ;
        else
          discriminator = fabs(DeltaZ) < cutDeltaZ;

        if (discriminator) {
          Pt_jets_X += track->px();
          Pt_jets_Y += track->py();
        }
      }
    }
  }
  double Var = -1;

  if (Algo == 1)
    Var = Track_Pt(Pt_jets_X, Pt_jets_Y) / jet_et;
  else if (Algo == 2) {
    if (Track_Pt(Pt_jets_X_tot, Pt_jets_Y_tot) != 0)
      Var = Track_Pt(Pt_jets_X, Pt_jets_Y) / Track_Pt(Pt_jets_X_tot, Pt_jets_Y_tot);
    else
      std::cout << "[Jets] JetVertexAssociation: Warning! problems for  Algo = 2: possible division by zero .."
                << std::endl;
  } else {
    Var = Track_Pt(Pt_jets_X, Pt_jets_Y) / jet_et;
    std::cout << "[Jets] JetVertexAssociation: Warning! Algo = " << Algo << " not found; using Algo = 1" << std::endl;
  }

  //  cout<<"Var = "<<Var<<endl;

  if (Var >= threshold)
    parameter = std::pair<double, bool>(Var, true);
  else
    parameter = std::pair<double, bool>(Var, false);

  return parameter;
}

double JetVertexMain::DeltaR(double eta1, double eta2, double phi1, double phi2) const {
  double dphi = fabs(phi1 - phi2);
  if (dphi > M_PI)
    dphi = 2 * M_PI - dphi;
  double deta = fabs(eta1 - eta2);
  return sqrt(dphi * dphi + deta * deta);
}

double JetVertexMain::Track_Pt(double px, double py) const { return sqrt(px * px + py * py); }