ElectronTraits.h

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// emacs: this is -*- c++ -*-
 
#ifndef  IDTPM2_ELECTRONTRAITS_H
#define  IDTPM2_ELECTRONTRAITS_H
 
#include "xAODEgamma/ElectronContainer.h"
 
#include "TrackTraits.h"
 
 
template<>
struct TrackTraits<xAOD::Electron> : public TrackTraitsBase<xAOD::Electron> {
  
public:
  
  static uint8_t summary_value( const xAOD::Electron& e, xAOD::SummaryType type ) {
    uint8_t n(0); e.trackParticle()->summaryValue(n, type); return n;
  }
  
  static float     pt(const xAOD::Electron& e) { return e.pt(); }
  static float    eta(const xAOD::Electron& e) { return e.eta();    } 
  static float  theta(const xAOD::Electron& e) { return 2*std::atan(std::exp(-e.eta()));  }
  static float    phi(const xAOD::Electron& e) { return e.phi(); }
 
  static float      m(const xAOD::Electron& e) { return e.m(); }
 
  static float     z0(const xAOD::Electron& e) { return e.trackParticle()->z0() + e.trackParticle()->vz(); }
  static float     d0(const xAOD::Electron& e) { return e.trackParticle()->d0(); }
 
  static float qOverP(const xAOD::Electron& e) { return e.trackParticle()->qOverP(); }

  static float      p(const xAOD::Electron& e) { 
    if ( e.trackParticle()->qOverP()==0 ) throw std::runtime_error( "divide by 0 - track qOverP() is 0" );
    return 1/e.trackParticle()->qOverP();
  }
 
  static float      E(const xAOD::Electron& e) { return e.e(); }
 
  static float     ET(const xAOD::Electron& e) { return e.e()*std::sin(theta(e)); }
 
 
#if 0
  static float     dphi(const xAOD::Electron& e) { return std::sqrt(e.trackParticle()->definingParametersCovMatrix()(Trk::phi0,Trk::phi0)); }
  static float   dtheta(const xAOD::Electron& e) { return std::sqrt(e.trackParticle()->definingParametersCovMatrix()(Trk::theta,Trk::theta)); }
  static float  dqOverP(const xAOD::Electron& e) { return std::sqrt(e.trackParticle()->definingParametersCovMatrix()(Trk::qOverP,Trk::qOverP)); }
  
  static float     deta(const xAOD::Electron& e) { return 0.5*dtheta(e)/(std::cos(0.5*theta(e))*std::cos(0.5*theta(e))*std::tan(0.5*theta(e))); }  // ???? CHECK THIS <<--
 
  static float      dz0(const xAOD::Electron& e) { return std::sqrt(e.trackParticle()->definingParametersCovMatrix()(Trk::z0,Trk::z0)); }
  static float      dd0(const xAOD::Electron& e) { return std::sqrt(e.trackParticle()->definingParametersCovMatrix()(Trk::d0,Trk::d0)); }
  
  static float dpt(const xAOD::Electron& e) {
    double th  = theta(e);
    double dth = dtheta(e);
    double sintheta = std::sin(th);
    double costheta = std::cos(th);
    double p_ = p(e);
    double dqovp = dqOverP(e);
    double dpt2 = (p_*p_*sintheta)*(p_*p_*sintheta)*dqovp*dqovp + (p_*costheta)*(p_*costheta)*dth*dth - 2*(p_*p_*sintheta)*(p_*costheta)*covthetaOvP(e);    
    if ( dpt2>0 ) return std::sqrt( dpt2 );
    return 0;
  }
  
  static float covthetaOvP(const xAOD::Electron& e) { return e.trackParticle()->definingParametersCovMatrix()(Trk::qOverP,Trk::theta); }; 
  
  static float chi2(const xAOD::Electron& e) { return e.trackParticle()->chiSquared(); }
  static float ndof(const xAOD::Electron& e) { return e.trackParticle()->numberDoF();  }  
  
  static uint8_t hasValidTime(const xAOD::Electron& e) { return e.trackParticle()->hasValidTime(); }
  static float           time(const xAOD::Electron& e) { return e.trackParticle()->time(); }
 
  //  static float      pTsig(const xAOD::Electron& t) { return t.charge() ? std::copysign( t.pt(), t.charge() ) : 0.; }
  //  static float z0SinTheta(const xAOD::Electron& t) { return z0( p ) * std::sin( theta( p ) ); }
  
#endif  
  
  template<typename U>
  static void    addChildren( const xAOD::Electron& e, std::vector<U>& v ) { v.emplace_back( e.trackParticle() ); }
  
};
 
 
 
 
#endif  // IDTPM2_ELECTRONTRAITS_H