#include <PythiaDecays.h>

Public Member Functions
const DaughterParticleList &	particleDaughtersPy6 (ParticlePropagator &particle, CLHEP::HepRandomEngine *)

const DaughterParticleList &	particleDaughtersPy8 (ParticlePropagator &particle, CLHEP::HepRandomEngine *)

	PythiaDecays (std::string program)

	~PythiaDecays ()

Private Attributes
std::auto_ptr< Pythia8::Pythia >	decayer

std::unique_ptr < gen::P8RndmEngine >	p8RndmEngine

std::string	program_

Pythia6jets *	pyjets

gen::Pythia6Service *	pyservice

DaughterParticleList	theList

Detailed Description

Definition at line 34 of file PythiaDecays.h.

Constructor & Destructor Documentation

PythiaDecays::PythiaDecays ( std::string program )

Definition at line 23 of file PythiaDecays.cc.

References gather_cfg::cout, decayer, p8RndmEngine, sysUtil::pid, program_, pyjets, pyservice, and Pythia6jets::Pythia6jets().

 {
   program_=program;
   if (program_ == "pythia6") {
     pyjets = new Pythia6jets();
     pyservice = new gen::Pythia6Service();
     // The PYTHIA decay tables will be initialized later 
   } else if (program_ == "pythia8") {
 
 
     // inspired by method Pythia8Hadronizer::residualDecay() in GeneratorInterface/Pythia8Interface/src/Py8GunBase.cc
     decayer.reset(new Pythia8::Pythia);
     p8RndmEngine.reset(new gen::P8RndmEngine);
     decayer->setRndmEnginePtr(p8RndmEngine.get());
     decayer->settings.flag("ProcessLevel:all",false);
     decayer->settings.flag("PartonLevel:FSRinResonances",false);
     decayer->settings.flag("ProcessLevel:resonanceDecays",false);
     decayer->init();
 
     // forbid all decays    
     Pythia8::ParticleData & pdt = decayer->particleData;
     int pid = 1;
     while(pdt.nextId(pid) > pid){
       pid = pdt.nextId(pid);
       pdt.mayDecay(pid,false);
     }
 
   } else {
     std::cout << "WARNING: you are requesting an option which is not available in PythiaDecays::PythiaDecays " << std::endl;
   }
 
 }

PythiaDecays::~PythiaDecays ( )

Definition at line 58 of file PythiaDecays.cc.

References program_, pyjets, and pyservice.

                             {
   if (program_ == "pythia6") {
     delete pyjets;
     delete pyservice;
   }
 }

Member Function Documentation

const DaughterParticleList & PythiaDecays::particleDaughtersPy6	(	ParticlePropagator &	particle,
		CLHEP::HepRandomEngine *	engine
	)

Definition at line 111 of file PythiaDecays.cc.

References i, Pythia6jets::k(), RawParticle::mass(), bookConverter::max, Pythia6jets::n(), Pythia6jets::p(), RawParticle::pid(), pyjets, pyservice, PYTHIA6PYDECY, RawParticle::T(), theList, Pythia6jets::v(), RawParticle::X(), RawParticle::Y(), and RawParticle::Z().

Referenced by TrajectoryManager::updateWithDaughters().

 {
   edm::RandomEngineSentry<gen::Pythia6Service> sentry(pyservice, engine);
 
   gen::Pythia6Service::InstanceWrapper guard(pyservice); // grab Py6 context
 
   //  Pythia6jets pyjets;
   int ip;
 
   pyjets->k(1,1) = 1;
   pyjets->k(1,2) = particle.pid();
   pyjets->p(1,1) = particle.Px();
   pyjets->p(1,2) = particle.Py();
   pyjets->p(1,3) = particle.Pz();
   pyjets->p(1,4) = std::max(particle.mass(),particle.e());
   pyjets->p(1,5) = particle.mass();
   pyjets->v(1,1) = particle.X();
   pyjets->v(1,2) = particle.Y();
   pyjets->v(1,3) = particle.Z();
   pyjets->v(1,4) = particle.T();
   pyjets->n() = 1;
   
   ip = 1;
   PYTHIA6PYDECY(&ip);
 
   // Fill the list of daughters
   theList.clear();
   if ( pyjets->n()==1 ) return theList; 
 
   theList.resize(pyjets->n()-1,RawParticle());
 
   for (int i=2;i<=pyjets->n();++i) {
     
     theList[i-2].SetXYZT(pyjets->p(i,1),pyjets->p(i,2),
              pyjets->p(i,3),pyjets->p(i,4)); 
     theList[i-2].setVertex(pyjets->v(i,1),pyjets->v(i,2),
                pyjets->v(i,3),pyjets->v(i,4));
     theList[i-2].setID(pyjets->k(i,2));
     theList[i-2].setMass(pyjets->p(i,5));
 
   }
 
   return theList;
   
 }

const DaughterParticleList & PythiaDecays::particleDaughtersPy8	(	ParticlePropagator &	particle,
		CLHEP::HepRandomEngine *	engine
	)

Definition at line 66 of file PythiaDecays.cc.

References decayer, RawParticle::mass(), RawParticle::momentum(), p8RndmEngine, sysUtil::pid, RawParticle::pid(), RawParticle::T(), theList, RawParticle::X(), RawParticle::Y(), and RawParticle::Z().

Referenced by TrajectoryManager::updateWithDaughters().

 {
   edm::RandomEngineSentry<gen::P8RndmEngine> sentry(p8RndmEngine.get(), engine);
 
   theList.clear();
 
   // inspired by method Pythia8Hadronizer::residualDecay() in GeneratorInterface/Pythia8Interface/src/Py8GunBase.cc
   int pid = particle.pid();
   decayer->event.reset();
   Pythia8::Particle py8part( pid , 93, 0, 0, 0, 0, 0, 0,
              particle.momentum().x(), // note: momentum().x() and Px() are the same
              particle.momentum().y(),
              particle.momentum().z(),
              particle.momentum().t(),
              particle.mass() );
   py8part.vProd( particle.X(), particle.Y(), 
          particle.Z(), particle.T() );
   decayer->event.append( py8part );
 
   int nentries_before = decayer->event.size();
   decayer->particleData.mayDecay(pid,true);   // switch on the decay of this and only this particle (avoid double decays)
   decayer->next();                           // do the decay
   decayer->particleData.mayDecay(pid,false);  // switch it off again
   int nentries_after = decayer->event.size();
   if ( nentries_after <= nentries_before ) return theList;
 
   theList.resize(nentries_after - nentries_before,RawParticle());
 
 
   for ( int ipart=nentries_before; ipart<nentries_after; ipart++ )
     {
       Pythia8::Particle& py8daughter = decayer->event[ipart];
       theList[ipart-nentries_before].SetXYZT( py8daughter.px(), py8daughter.py(), py8daughter.pz(), py8daughter.e() );
       theList[ipart-nentries_before].setVertex( py8daughter.xProd(),
                        py8daughter.yProd(),
                        py8daughter.zProd(),
                        py8daughter.tProd() );
       theList[ipart-nentries_before].setID( py8daughter.id() );
       theList[ipart-nentries_before].setMass( py8daughter.m() );
     }
 
   return theList;
 }