//=============================================================================
// Main execution
//=============================================================================
StatusCode ParticleGunAlg::execute() {
StatusCode sc = StatusCode::SUCCESS ;
Gaudi::LorentzVector theFourMomentum ;
Gaudi::LorentzVector origin ;
int thePdgId ;
// prepare a new HepMC event
HepMC::GenEvent * theEvent = new HepMC::GenEvent() ;
m_particleGunTool->generateParticle( theFourMomentum , origin , thePdgId );
// create HepMC Vertex
HepMC::GenVertex * v = new HepMC::GenVertex( HepMC::FourVector( origin.X() ,
origin.Y() ,
origin.Z() ,
origin.T() ) ) ;
// create HepMC particle
HepMC::GenParticle * p = new HepMC::GenParticle( HepMC::FourVector( theFourMomentum.Px() ,
theFourMomentum.Py() ,
theFourMomentum.Pz() ,
theFourMomentum.E() ) ,
thePdgId ,
3 ) ;
v -> add_particle_out( p ) ;
theEvent -> add_vertex( v ) ;
theEvent -> set_signal_process_id( 0 ) ;
theEvent -> set_signal_process_vertex( v ) ;
if(m_vertexSmearTool != nullptr)
m_vertexSmearTool->smearVertex(theEvent);
HepMCEntry * entry = new HepMCEntry();
entry->setEvent(theEvent);
m_hepmchandle.put(entry);
return sc ;
}
StatusCode ConstPtParticleGun::getNextEvent(HepMC::GenEvent& theEvent) {
Gaudi::LorentzVector theFourMomentum;
Gaudi::LorentzVector origin;
// note: pgdid is set in function generateParticle
int thePdgId;
generateParticle(theFourMomentum, origin, thePdgId);
// create HepMC Vertex --
// by calling add_vertex(), the hepmc event is given ownership of the vertex
HepMC::GenVertex* v = new HepMC::GenVertex(HepMC::FourVector(origin.X(), origin.Y(), origin.Z(), origin.T()));
// create HepMC particle --
// by calling add_particle_out(), the hepmc vertex is given ownership of the particle
HepMC::GenParticle* p = new HepMC::GenParticle(
HepMC::FourVector(theFourMomentum.Px(), theFourMomentum.Py(), theFourMomentum.Pz(), theFourMomentum.E()),
thePdgId,
1); // hepmc status code for final state particle
v->add_particle_out(p);
theEvent.add_vertex(v);
theEvent.set_signal_process_vertex(v);
return StatusCode::SUCCESS;
}