PdgToParticleHypothesis.icc

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/*
  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
*/
 
namespace Trk {
inline Trk::ParticleHypothesis
PdgToParticleHypothesis::convert(int pdg, double charge) const
{
  bool stable, exiting;
  return convert(pdg, stable, exiting, charge);
}
 
inline Trk::ParticleHypothesis
PdgToParticleHypothesis::convert(int pdg,
                                 bool& stable,
                                 bool& exiting,
                                 double charge) const
{
 
  int pdgCode = abs(pdg);
 
  stable = false;
  exiting = false;
 
  Trk::ParticleHypothesis particleType;
 
  // try to follow number of appearance
  switch (pdgCode) {
      // leptons
    case 11: { // e+/e-
      particleType = Trk::electron;
      stable = true;
      exiting = false;
      break;
    }
    case 13: { // mu+/mu-
      particleType = Trk::muon;
      stable = false;
      exiting = false;
      break;
    }
    case 12:   // e neutrino
    case 14:   // mu neutrino
    case 16: { // tau neutrino
      particleType = Trk::nonInteracting;
      stable = true;
      exiting = true;
      break;
    }
    case 22: { // gamma
      particleType = Trk::photon;
      stable = true;
      exiting = false;
      break;
    }
    case 211: { // pi+/pi-
      particleType = Trk::pion;
      stable = false;
      exiting = false;
      break;
    }
    case 111: { // pi0
      particleType = Trk::pi0;
      stable = false;
      exiting = false;
      break;
    }
    case 2212: { // proton
      particleType = Trk::proton;
      stable = true;
      exiting = false;
      break;
    }
    case 2112: { // neutron
      particleType = Trk::neutron;
      stable = true;
      exiting = true;
      break;
    }
    case 321: { // K
      particleType = Trk::kaon;
      stable = false;
      exiting = false;
      break;
    }
    case 130: { // K_long
      particleType = Trk::k0;
      stable = false;
      exiting = false;
      break;
    }
    case 310: { // K_short
      particleType = Trk::k0;
      stable = false;
      exiting = false;
      break;
    }
    default: { // treat mesons as pions
      particleType = charge != 0. ? Trk::pion : Trk::pi0;
      stable = false;
      exiting = false;
    }
  }
 
  // and all baryons as proton hypo
  if (pdgCode > 999 && pdgCode != 2112) {
    particleType = charge != 0. ? Trk::proton : Trk::neutron;
    stable = false;
    exiting = false;
  }
 
  // ignore SUSY particles for now
  if (pdgCode > 1000000) {
    particleType = Trk::nonInteracting;
    stable = true;
    exiting = true;
  }
 
  return particleType;
}
 
inline int
PdgToParticleHypothesis::convert(Trk::ParticleHypothesis particleHypo,
                                 double charge,
                                 bool dist) const
{
 
  int pdg = 0;
 
  switch (particleHypo) {
      // the electron case
    case Trk::electron: {
      pdg = 11;
      pdg *= charge > 0. ? -1 : 1;
      return pdg;
    }
      // the muon case
    case Trk::muon: {
      pdg = 13;
      pdg *= charge > 0. ? -1 : 1;
      return pdg;
    }
      // the kaon case
    case Trk::kaon: {
      pdg = 321;
      pdg *= charge > 0. ? 1 : -1;
      if (charge * charge < 0.0001)
        pdg = dist ? 130 : 310;
      return pdg;
    }
      // the proton case
    case Trk::proton: {
      pdg = 2212;
      pdg *= charge > 0. ? 1 : -1;
      if (charge * charge < 0.0001)
        pdg = dist ? 2112 : -2112;
      return pdg;
    }
      // the photon case
    case Trk::photon: {
      pdg = 22;
      return pdg;
    }
      // the neutron case
    case Trk::neutron: {
      pdg = 2112;
      return pdg;
    }
      // the neutral pion case
    case Trk::pi0: {
      pdg = 111;
      return pdg;
    }
      // the neutral kaon case
    case Trk::k0: {
      pdg = dist ? 130 : 310;
      return pdg;
    }
      // the pion case - is the default
    default: {
      pdg = 211;
      pdg *= charge > 0. ? 1 : -1;
      if (charge * charge < 0.0001)
        pdg = 111;
    }
  }
 
  return pdg;
}
}