void Output_Delphes::AnalyseParticles(ExRootTreeBranch *branch, const HepMC::GenEvent& evt)
{
TRootC::GenParticle *element;
TLorentzVector momentum;
Double_t signPz;
ReadStats();
for(int n=1; n<=evt.particles_size(); n++) {
int mo1, mo2, da1, da2, status, pid;
getStatsFromTuple(mo1,mo2,da1,da2,status,pid,n);
element = static_cast<TRootC::GenParticle*>(branch->NewEntry());
element->PID = pid;
element->Status = status;
element->M1 = mo1 - 1; // added -1 as the numbering in the tree starts from 0
element->M2 = mo2 - 1;
element->D1 = da1 - 1;
element->D2 = da2 - 1;
element->E = index_to_particle[n]->momentum().e();
element->Px = index_to_particle[n]->momentum().px();
element->Py = index_to_particle[n]->momentum().py();
element->Pz = index_to_particle[n]->momentum().pz();
element->PT = sqrt(pow(element->Px,2)+pow(element->Py,2));
momentum.SetPxPyPzE(element->Px, element->Py, element->Pz, element->E);
signPz = (element->Pz >= 0.0) ? 1.0 : -1.0;
element->Eta = element->PT < 1e-6 ? signPz*999.9 : momentum.Eta();
element->Phi = index_to_particle[n]->momentum().phi();
HepMC::GenVertex* vrtI = (index_to_particle[n])->production_vertex();
HepMC::GenVertex::particles_in_const_iterator partI;
if(vrtI) {
element->T = vrtI->position().t();
element->X = vrtI->position().x();
element->Y = vrtI->position().y();
element->Z = vrtI->position().z();
}
else {
element->T = 0.;
element->X = 0.;
element->Y = 0.;
element->Z = 0.;
}
}
}
StatusCode HepMCToEDMConverter::execute() {
const HepMC::GenEvent* event = m_hepmchandle.get();
fcc::MCParticleCollection* particles = new fcc::MCParticleCollection();
fcc::GenVertexCollection* vertices = new fcc::GenVertexCollection();
// conversion of units to EDM standard units:
// First cover the case that hepMC file is not in expected units and then convert to EDM default
double hepmc2EdmLength =
HepMC::Units::conversion_factor(event->length_unit(), gen::hepmcdefault::length) * gen::hepmc2edm::length;
double hepmc2EdmEnergy =
HepMC::Units::conversion_factor(event->momentum_unit(), gen::hepmcdefault::energy) * gen::hepmc2edm::energy;
// bookkeeping of particle / vertex relations
std::unordered_map<const HepMC::GenVertex*, fcc::GenVertex> hepmcToEdmVertexMap;
HepMC::FourVector tmp; /// temp variable for the transfer of position / momentom
// iterate over particles in event
for (auto particle_i = event->particles_begin(); particle_i != event->particles_end(); ++particle_i) {
// if there is a list of statuses to filter: filter by status
if(std::find(m_hepmcStatusList.begin(), m_hepmcStatusList.end(), (*particle_i)->status()) == m_hepmcStatusList.end() && m_hepmcStatusList.size() > 0) continue;
// create edm
fcc::MCParticle particle = particles->create();
// set mcparticle data members
particle.pdgId((*particle_i)->pdg_id());
particle.status((*particle_i)->status());
/// lookup charge in particle properties
HepPDT::ParticleID particleID((*particle_i)->pdg_id());
particle.charge(particleID.charge());
auto& p4 = particle.p4();
tmp = (*particle_i)->momentum();
p4.px = tmp.px() * hepmc2EdmEnergy;
p4.py = tmp.py() * hepmc2EdmEnergy;
p4.pz = tmp.pz() * hepmc2EdmEnergy;
p4.mass = (*particle_i)->generated_mass() * hepmc2EdmEnergy;
/// create production vertex, if it has not already been created and logged in the map
HepMC::GenVertex* productionVertex = (*particle_i)->production_vertex();
if (nullptr != productionVertex) {
if (hepmcToEdmVertexMap.find(productionVertex) != hepmcToEdmVertexMap.end()) {
// vertex already in map, no need to create a new one
particle.startVertex(hepmcToEdmVertexMap[productionVertex]);
} else {
tmp = productionVertex->position();
auto vertex = vertices->create();
auto& position = vertex.position();
position.x = tmp.x() * hepmc2EdmLength;
position.y = tmp.y() * hepmc2EdmLength;
position.z = tmp.z() * hepmc2EdmLength;
vertex.ctau(tmp.t() * Gaudi::Units::c_light * hepmc2EdmLength); // is ctau like this?
// add vertex to map for further particles
hepmcToEdmVertexMap.insert({productionVertex, vertex});
particle.startVertex(vertex);
}
}
/// create decay vertex, if it has not already been created and logged in the map
HepMC::GenVertex* decayVertex = (*particle_i)->end_vertex();
if (nullptr != decayVertex) {
if (hepmcToEdmVertexMap.find(decayVertex) != hepmcToEdmVertexMap.end()) {
// vertex already in map, no need to create a new one
particle.endVertex(hepmcToEdmVertexMap[decayVertex]);
} else {
tmp = decayVertex->position();
auto vertex = vertices->create();
auto& position = vertex.position();
position.x = tmp.x() * hepmc2EdmLength;
position.y = tmp.y() * hepmc2EdmLength;
position.z = tmp.z() * hepmc2EdmLength;
vertex.ctau(tmp.t() * Gaudi::Units::c_light * hepmc2EdmLength); // is ctau like this?
// add vertex to map for further particles
hepmcToEdmVertexMap.insert({decayVertex, vertex});
particle.endVertex(vertex);
}
}
} // particle loop
m_genphandle.put(particles);
m_genvhandle.put(vertices);
return StatusCode::SUCCESS;
}
