TrackJet.h

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/*
  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
*/

// TrackJet.h
//   Header file for TrackJet helper class
// (c) ATLAS Detector software
 
#ifndef TRK_TRKVALEVENT_TRACKJET_H
#define TRK_TRKVALEVENT_TRACKJET_H
 
#include <vector>
#include "TrkEventPrimitives/GlobalMomentum.h"
#include "TrkParameters/Perigee.h"
#include "TrkTrack/Track.h"
 
namespace Trk {

 
class TrackJet
{
  
 public:
  TrackJet(): m_tracks(), m_energy(0.), m_momentum(0.0, 0.0, 0.0), m_totalPt2(0.), m_totalMom2(0.), m_pDotJetAxis(0.), m_magP(0.)
    {
        
    };

  TrackJet(const TrackJet &a){
       m_tracks = a.m_tracks;
       m_energy = a.m_energy;
       m_momentum = a.m_momentum;
       m_totalPt2 = a.m_totalPt2;
       m_totalMom2 = a.m_totalMom2;
       m_pDotJetAxis = a.m_pDotJetAxis;
       m_magP = a.m_magP;
  };

  ~TrackJet(){}; // destructor
  
  void setEnergy(double energy){m_energy = energy;}
 
  double getEnergy(){return m_energy;}
  
  Trk::Track* getTrack(unsigned int i)
    {
      return m_tracks.at(i);
    }
  
  std::vector<Trk::Track* > getTracks(){return m_tracks;}
 
  int getNumTracks(){return m_tracks.size();}

  void addTrack(Trk::Track* trk){
    m_tracks.push_back(trk);
    m_energy = m_energy + thisEnergy(trk);
    HepGeom::Vector3D<double> moment = trk->perigeeParameters()->momentum();
    m_momentum = m_momentum + moment;
 
    double longMoment = fabs((trk->perigeeParameters()->momentum()).dot((m_momentum)/(m_momentum.mag())));
    m_totalPt2 = m_totalPt2 + pow(trk->perigeeParameters()->momentum().mag(), 2) - pow((longMoment), 2);
    m_pDotJetAxis = m_pDotJetAxis + longMoment;
    m_magP = m_magP + trk->perigeeParameters()->momentum().mag();
    m_totalMom2 = m_totalMom2 + pow((trk->perigeeParameters()->momentum().mag()), 2);
  }
 
  HepGeom::Vector3D<double> getMomentum(){return m_momentum;}
 
  double getThrust(){return m_pDotJetAxis/m_magP;}
  double getSphericity(){return m_totalPt2/m_totalMom2;}
 
 private:
 
  std::vector<Trk::Track* > m_tracks;
  double m_energy;
  HepGeom::Vector3D<double> m_momentum;
  double m_totalPt2;
  double m_totalMom2;
  double m_pDotJetAxis;
  double m_magP;
 
  double thisEnergy(const Trk::Track* i)
    {
      HepGeom::Vector3D<double> moment = i->perigeeParameters()->momentum();
      return sqrt(moment.dot(moment) +ParticleConstants::chargedPionMassInMeV*ParticleConstants::chargedPionMassInMeV );
    }
};
 
} // end of namespace
 
#endif // TRK_TRKVALEVENT_TRACKJET_H