genie::PhotonCOHGenerator Class Reference

Generator for W boson production. More...

#include <PhotonCOHGenerator.h>

Inheritance diagram for genie::PhotonCOHGenerator:

Collaboration diagram for genie::PhotonCOHGenerator:

Public Member Functions
	PhotonCOHGenerator ()
	PhotonCOHGenerator (string config)
	~PhotonCOHGenerator ()
void	Initialize (void) const
void	ProcessEventRecord (GHepRecord *evrec) const
void	Configure (const Registry &config)
void	Configure (string config)
Public Member Functions inherited from genie::EventRecordVisitorI
virtual	~EventRecordVisitorI ()
Public Member Functions inherited from genie::Algorithm
virtual	~Algorithm ()
virtual void	FindConfig (void)
virtual const Registry &	GetConfig (void) const
Registry *	GetOwnedConfig (void)
virtual const AlgId &	Id (void) const
	Get algorithm ID. More...
virtual AlgStatus_t	GetStatus (void) const
	Get algorithm status. More...
virtual bool	AllowReconfig (void) const
virtual AlgCmp_t	Compare (const Algorithm *alg) const
	Compare with input algorithm. More...
virtual void	SetId (const AlgId &id)
	Set algorithm ID. More...
virtual void	SetId (string name, string config)
const Algorithm *	SubAlg (const RgKey &registry_key) const
void	AdoptConfig (void)
void	AdoptSubstructure (void)
virtual void	Print (ostream &stream) const
	Print algorithm info. More...

Private Member Functions
void	LoadConfig (void)

Private Attributes
TPythia6 *	fPythia
	PYTHIA6 wrapper class. More...

Additional Inherited Members
Static Public Member Functions inherited from genie::Algorithm
static string	BuildParamVectKey (const std::string &comm_name, unsigned int i)
static string	BuildParamVectSizeKey (const std::string &comm_name)
static string	BuildParamMatKey (const std::string &comm_name, unsigned int i, unsigned int j)
static string	BuildParamMatRowSizeKey (const std::string &comm_name)
static string	BuildParamMatColSizeKey (const std::string &comm_name)
Protected Member Functions inherited from genie::EventRecordVisitorI
	EventRecordVisitorI ()
	EventRecordVisitorI (string name)
	EventRecordVisitorI (string name, string config)
Protected Member Functions inherited from genie::Algorithm
	Algorithm ()
	Algorithm (string name)
	Algorithm (string name, string config)
void	Initialize (void)
void	DeleteConfig (void)
void	DeleteSubstructure (void)
Registry *	ExtractLocalConfig (const Registry &in) const
Registry *	ExtractLowerConfig (const Registry &in, const string &alg_key) const
	Split an incoming configuration Registry into a block valid for the sub-algo identified by alg_key. More...
template<class T >
bool	GetParam (const RgKey &name, T &p, bool is_top_call=true) const
template<class T >
bool	GetParamDef (const RgKey &name, T &p, const T &def) const
template<class T >
int	GetParamVect (const std::string &comm_name, std::vector< T > &v, bool is_top_call=true) const
	Handle to load vectors of parameters. More...
int	GetParamVectKeys (const std::string &comm_name, std::vector< RgKey > &k, bool is_top_call=true) const
template<class T >
int	GetParamMat (const std::string &comm_name, TMatrixT< T > &mat, bool is_top_call=true) const
	Handle to load matrix of parameters. More...
template<class T >
int	GetParamMatSym (const std::string &comm_name, TMatrixTSym< T > &mat, bool is_top_call=true) const
int	GetParamMatKeys (const std::string &comm_name, std::vector< RgKey > &k, bool is_top_call=true) const
int	AddTopRegistry (Registry *rp, bool owns=true)
	add registry with top priority, also update ownership More...
int	AddLowRegistry (Registry *rp, bool owns=true)
	add registry with lowest priority, also update ownership More...
int	MergeTopRegistry (const Registry &r)
int	AddTopRegisties (const vector< Registry * > &rs, bool owns=false)
	Add registries with top priority, also udated Ownerships. More...
Protected Attributes inherited from genie::Algorithm
bool	fAllowReconfig
bool	fOwnsSubstruc
	true if it owns its substructure (sub-algs,...) More...
AlgId	fID
	algorithm name and configuration set More...
vector< Registry * >	fConfVect
vector< bool >	fOwnerships
	ownership for every registry in fConfVect More...
AlgStatus_t	fStatus
	algorithm execution status More...
AlgMap *	fOwnedSubAlgMp
	local pool for owned sub-algs (taken out of the factory pool) More...

Detailed Description

Generator for W boson production.

Author

Alfonso Garcia <aagarciasoto km3net.de> IFIC & Harvard University

Created:

Dec 8, 2021

License:

Copyright (c) 2003-2024, The GENIE Collaboration For the full text of the license visit http://copyright.genie-mc.org or see $GENIE/LICENSE

Definition at line 29 of file PhotonCOHGenerator.h.

Constructor & Destructor Documentation

PhotonCOHGenerator::PhotonCOHGenerator

(

)

Definition at line 41 of file PhotonCOHGenerator.cxx.

References Initialize().

                                       :
EventRecordVisitorI("genie::PhotonCOHGenerator")
{
  this->Initialize();
}

PhotonCOHGenerator::PhotonCOHGenerator

(

string

config

)

Definition at line 47 of file PhotonCOHGenerator.cxx.

References Initialize().

                                                    :
EventRecordVisitorI("genie::PhotonCOHGenerator", config)
{
  this->Initialize();
}

PhotonCOHGenerator::~PhotonCOHGenerator

(

)

Definition at line 53 of file PhotonCOHGenerator.cxx.

{

}

Member Function Documentation

void PhotonCOHGenerator::Configure ( const Registry &  config )

virtual

Configure the algorithm with an external registry The registry is merged with the top level registry if it is owned, Otherwise a copy of it is added with the highest priority

Reimplemented from genie::Algorithm.

Definition at line 221 of file PhotonCOHGenerator.cxx.

References genie::Algorithm::Configure(), and LoadConfig().

{
  Algorithm::Configure(config);
  this->LoadConfig();
}

void PhotonCOHGenerator::Configure ( string  config )

virtual

Configure the algorithm from the AlgoConfigPool based on param_set string given in input An algorithm contains a vector of registries coming from different xml configuration files, which are loaded according a very precise prioriy This methods will load a number registries in order of priority: 1) "Tunable" parameter set from CommonParametes. This is loaded with the highest prioriry and it is designed to be used for tuning procedure Usage not expected from the user. 2) For every string defined in "CommonParame" the corresponding parameter set will be loaded from CommonParameter.xml 3) parameter set specified by the config string and defined in the xml file of the algorithm 4) if config is not "Default" also the Default parameter set from the same xml file will be loaded Effectively this avoids the repetion of a parameter when it is not changed in the requested configuration

Reimplemented from genie::Algorithm.

Definition at line 227 of file PhotonCOHGenerator.cxx.

References genie::Algorithm::Configure(), and LoadConfig().

{
  Algorithm::Configure(config);
  this->LoadConfig();
}

void PhotonCOHGenerator::Initialize

(

void

)

const

Definition at line 58 of file PhotonCOHGenerator.cxx.

References fPythia, and genie::RandomGen::Instance().

Referenced by PhotonCOHGenerator().

{
  fPythia = TPythia6::Instance();

  // sync GENIE/PYTHIA6 seed number                                                                                                                                   
  RandomGen::Instance();
}

void PhotonCOHGenerator::LoadConfig ( void  )

private

Definition at line 233 of file PhotonCOHGenerator.cxx.

References fPythia, genie::Algorithm::GetParam(), and genie::constants::kMw.

Referenced by Configure().

{

  // PYTHIA parameters only valid for HEDIS & HELepton
  double wmin;        GetParam( "Xsec-Wmin",     wmin ) ;
  int warnings;       GetParam( "Warnings",      warnings ) ;
  int errors;         GetParam( "Errors",        errors ) ;
  int qrk_mass;       GetParam( "QuarkMass",     qrk_mass ) ;
  fPythia->SetPARP(2,  wmin);         //(D = 10. GeV) lowest c.m. energy for the event as a whole that the program will accept to simulate. (bellow 2GeV pythia crashes)
  fPythia->SetMSTU(26, warnings);     // (Default=10) maximum number of warnings that are printed
  fPythia->SetMSTU(22, errors);       // (Default=10) maximum number of errors that are printed
  fPythia->SetMSTJ(93, qrk_mass);     // light (d, u, s, c, b) quark masses are taken from PARF(101) - PARF(105) rather than PMAS(1,1) - PMAS(5,1). Diquark masses are given as sum of quark masses, without spin splitting term.

  fPythia->SetPMAS(24,1,kMw);  //mass of the W boson (pythia=80.450 // genie=80.385)
  fPythia->SetPMAS(24,2,0.);   //set to 0 the width of the W boson to avoid problems with energy conservation
  fPythia->SetPMAS(6,2,0.);    //set to 0 the width of the top to avoid problems with energy conservation

}

void PhotonCOHGenerator::ProcessEventRecord ( GHepRecord *  evrec ) const

virtual

Implements genie::EventRecordVisitorI.

Definition at line 66 of file PhotonCOHGenerator.cxx.

References genie::GHepRecord::AddParticle(), genie::utils::math::LongLorentzVector::BoostY(), genie::utils::math::LongLorentzVector::BoostZ(), genie::utils::math::LongLorentzVector::E(), genie::PDGLibrary::Find(), fPythia, genie::Kinematics::GetKV(), genie::Interaction::InitState(), genie::RandomGen::Instance(), genie::PDGLibrary::Instance(), genie::pdg::IsAntiNuE(), genie::pdg::IsAntiNuMu(), genie::pdg::IsAntiNuTau(), genie::pdg::IsNeutrino(), genie::pdg::IsNuE(), genie::pdg::IsNuMu(), genie::pdg::IsNuTau(), genie::constants::kElectronMass, genie::Interaction::Kine(), genie::kIStDISPreFragmHadronicState, genie::kIStFinalStateNuclearRemnant, genie::kIStStableFinalState, genie::kKVn1, genie::kKVn2, genie::kKVn3, genie::constants::kMuonMass, genie::constants::kMw, genie::constants::kMw2, genie::constants::kNeutronMass, genie::kPdgAntiMuon, genie::kPdgAntiTau, genie::kPdgElectron, genie::kPdgMuon, genie::kPdgPositron, genie::kPdgTau, genie::kPdgWM, genie::kPdgWP, genie::constants::kPi, genie::constants::kProtonMass, genie::kRfLab, genie::constants::kTauMass, LOG, genie::Target::N(), genie::GHepParticle::P4(), genie::GHepParticle::Pdg(), genie::GHepRecord::Probe(), genie::InitialState::ProbeE(), genie::InitialState::ProbePdg(), pWARN, genie::utils::math::LongLorentzVector::Px(), genie::utils::math::LongLorentzVector::Py(), genie::utils::math::LongLorentzVector::Pz(), genie::utils::kinematics::Q2(), genie::RandomGen::RndLep(), genie::GHepRecord::Summary(), genie::InitialState::Tgt(), genie::GHepParticle::X4(), and genie::Target::Z().

{

  Interaction * interaction = evrec->Summary();
  const InitialState & init_state = interaction->InitState();

  //incoming v & struck particle & remnant nucleus
  GHepParticle * nu = evrec->Probe();

  GHepParticle * target = evrec -> TargetNucleus();
  if(target) evrec->AddParticle(target->Pdg(), kIStFinalStateNuclearRemnant, 1,-1,-1,-1, *(target->P4()), *(target->X4()) );

  TVector3 unit_nu = nu->P4()->Vect().Unit();

  long double Ev = init_state.ProbeE(kRfLab); 

  long double Mtgt = init_state.Tgt().Z()*kProtonMass + init_state.Tgt().N()*kNeutronMass;

  long double n1 = interaction->Kine().GetKV(kKVn1);
  long double n2 = interaction->Kine().GetKV(kKVn2);
  long double n3 = interaction->Kine().GetKV(kKVn3);

  long double costh = n1;
  long double sinth = sqrtl(1-costh*costh);

  long double mlout = 0;
  if      (pdg::IsNuE  (TMath::Abs(nu->Pdg()))) mlout = kElectronMass;
  else if (pdg::IsNuMu (TMath::Abs(nu->Pdg()))) mlout = kMuonMass;
  else if (pdg::IsNuTau(TMath::Abs(nu->Pdg()))) mlout = kTauMass;
  long double mlout2 = mlout*mlout;

  long double mL      = mlout+kMw;
  long double Delta   = sqrtl( powl(2.*Ev*Mtgt-mL*mL,2)-4.*powl(Mtgt*mL,2) );
  long double s12_min = Ev/(2.*Ev+Mtgt)*(mL*mL+2.*Ev*Mtgt-Delta);
  long double s12_max = Ev/(2.*Ev+Mtgt)*(mL*mL+2.*Ev*Mtgt+Delta);
  long double s12     = expl( logl(s12_min)+(logl(s12_max)-logl(s12_min))*n2);
  long double Q2_min  = powl(s12,2)*Mtgt/(2.*Ev*(2.*Ev*Mtgt-s12));
  long double Q2_max  = s12 - mL*mL;
  double Q2  = expl( logl(Q2_min) + (logl(Q2_max)-logl(Q2_min))*n3 );
  double s_r = s12 - Q2;

  long double EW = (s_r+kMw2-mlout2)/sqrtl(s_r)/2.;
  long double El = (s_r-kMw2+mlout2)/sqrtl(s_r)/2.;
  long double p  = sqrtl( EW*EW - kMw2 );
  LongLorentzVector p4_lout( 0., -p*sinth, -p*costh, El );

  long double bz = 4.*Ev*Mtgt*Q2/(Q2+s_r)/(2.*Ev*Mtgt-Q2) - (2.*Ev*Mtgt+Q2)/(2.*Ev*Mtgt-Q2);
  long double by = sqrtl(Mtgt*powl(Q2+s_r,2)/(2.*Ev*Q2*(s_r+Q2-2.*Ev*Mtgt))+1.);

  p4_lout.BoostZ(-bz);
  p4_lout.BoostY(-by);
  
  TLorentzVector p4l_o(p4_lout.Px(),p4_lout.Py(),p4_lout.Pz(),p4_lout.E());
  p4l_o.RotateX((double)acosl(by)-kPi/2.);


  // Randomize transverse components
  RandomGen * rnd = RandomGen::Instance();
  double phi  = 2 * kPi * rnd->RndLep().Rndm();

  p4l_o.RotateZ(phi);

  //rotate from LAB=[0,0,Ev,Ev]->[px,py,pz,E]
  p4l_o.RotateUz(unit_nu);

  int pdglout = 0;
  if      (pdg::IsAntiNuE  (nu->Pdg())) pdglout = kPdgPositron;
  else if (pdg::IsNuE      (nu->Pdg())) pdglout = kPdgElectron;
  else if (pdg::IsAntiNuMu (nu->Pdg())) pdglout = kPdgAntiMuon;
  else if (pdg::IsNuMu     (nu->Pdg())) pdglout = kPdgMuon;
  else if (pdg::IsAntiNuTau(nu->Pdg())) pdglout = kPdgAntiTau;
  else if (pdg::IsNuTau    (nu->Pdg())) pdglout = kPdgTau;

  // Create a GHepParticle and add it to the event record
  evrec->AddParticle( pdglout,  kIStStableFinalState, 0, -1, -1, -1, p4l_o, *(nu->X4()) );

  int pdgboson = pdg::IsNeutrino(init_state.ProbePdg()) ? kPdgWP : kPdgWM;

  int def61  = fPythia->GetMSTP(61);  
  int def71  = fPythia->GetMSTP(71); 
  fPythia->SetMSTP(61,0);    // (Default=2) master switch for initial-state QCD and QED radiation.
  fPythia->SetMSTP(71,0);    // (Default=2) master switch for initial-state QCD and QED radiation.

  fPythia->Py1ent( -1, pdgboson, EW, acosl(costh), kPi/2. ); //k(1,2) = 2
  fPythia->Pyexec();

  fPythia->SetMSTP(61,def61);
  fPythia->SetMSTP(71,def71);

  fPythia->GetPrimaries();
  TClonesArray * pythia_particles = (TClonesArray *) fPythia->ImportParticles("All");
  int np = pythia_particles->GetEntries();
  assert(np>0);

  TMCParticle * particle = 0;
  TIter piter(pythia_particles);
  while( (particle = (TMCParticle *) piter.Next()) ) {
    
    int pdgc = particle->GetKF();
    int ks = particle->GetKS();
   
    LongLorentzVector p4longo(particle->GetPx(), particle->GetPy(), particle->GetPz(), particle->GetEnergy());
    p4longo.BoostZ(-bz);
    p4longo.BoostY(-by);
    
    TLorentzVector p4o(p4longo.Px(),p4longo.Py(),p4longo.Pz(),p4longo.E());
    p4o.RotateX((double)acosl(by)-kPi/2.);
    p4o.RotateZ(phi);
    p4o.RotateUz(unit_nu);

    TParticlePDG * part = PDGLibrary::Instance()->Find(pdgc);
    if ( (ks==1 || ks==4) && p4o.E() < part->Mass() ) {
      LOG("PhotonCOHGenerator", pWARN) << "Putting at rest one stable particle generated by PYTHIA because E < m";
      LOG("PhotonCOHGenerator", pWARN) << "PDG = " << pdgc << " // State = " << ks;
      LOG("PhotonCOHGenerator", pWARN) << "E = " << p4o.E() << " // |p| = " << TMath::Sqrt(p4o.P()); 
      LOG("PhotonCOHGenerator", pWARN) << "p = [ " << p4o.Px() << " , "  << p4o.Py() << " , "  << p4o.Pz() << " ]";
      LOG("PhotonCOHGenerator", pWARN) << "m    = " << p4o.M() << " // mpdg = " << part->Mass();
      p4o.SetXYZT(0,0,0,part->Mass());
    }

    // copy final state particles to the event record
    GHepStatus_t ist = (ks==1 || ks==4) ? kIStStableFinalState : kIStDISPreFragmHadronicState;

    // fix numbering scheme used for mother/daughter assignments
    int firstmother = -1;
    int lastmother  = -1;
    int firstchild  = -1;
    int lastchild   = -1;
    
    if (particle->GetParent()==0) {
      firstmother = 0;
    }
    else {
      firstmother = particle->GetParent() + 3;       
      if (particle->GetFirstChild()!=0) firstchild  = particle->GetFirstChild() + 3;
      if (particle->GetLastChild() !=0) lastchild   = particle->GetLastChild() + 3;

    }

    double lightspeed = 299792458e3; //c in mm/s. Used for time in PYTHIA t[s]=t_pythia[mm]/c[mm/s]
    double vx = nu->X4()->X() + particle->GetVx()*1e12; //pythia gives position in [mm] while genie uses [fm]
    double vy = nu->X4()->Y() + particle->GetVy()*1e12;
    double vz = nu->X4()->Z() + particle->GetVz()*1e12;
    double vt = nu->X4()->T() + particle->GetTime()/lightspeed;
    TLorentzVector pos( vx, vy, vz, vt );

    evrec->AddParticle(pdgc, ist, firstmother, lastmother, firstchild, lastchild, p4o, pos );

  }

  delete particle;
  pythia_particles->Clear("C");

}

Member Data Documentation

TPythia6* genie::PhotonCOHGenerator::fPythia

mutableprivate

PYTHIA6 wrapper class.

Definition at line 50 of file PhotonCOHGenerator.h.

Referenced by Initialize(), LoadConfig(), and ProcessEventRecord().

---

The documentation for this class was generated from the following files:

• PhotonCOHGenerator.h
• PhotonCOHGenerator.cxx