genie::LeptoHadPythia8 Class Reference

Provides access to the PYTHIA8 hadronization.
. More...

#include <LeptoHadPythia8.h>

Inheritance diagram for genie::LeptoHadPythia8:

Collaboration diagram for genie::LeptoHadPythia8:

Public Member Functions
	LeptoHadPythia8 ()
	LeptoHadPythia8 (string config)
virtual	~LeptoHadPythia8 ()
void	ProcessEventRecord (GHepRecord *event) 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.
virtual AlgStatus_t	GetStatus (void) const
	Get algorithm status.
virtual bool	AllowReconfig (void) const
virtual AlgCmp_t	Compare (const Algorithm *alg) const
	Compare with input algorithm.
virtual void	SetId (const AlgId &id)
	Set algorithm ID.
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.

Private Member Functions
bool	Hadronize (GHepRecord *event) const
void	Initialize (void) const
void	LoadConfig (void)
int	getMeson (int, int, double) const
	create meson
int	getBaryon (int, int, double) const
	create baryon
double	getRandomZ (double, double) const
	fragmentation

Private Attributes
double	Afrag
	fragmentation parameter
double	Bfrag
	fragmentation parameter
double	mesonRateSum [3]
	meson parameter
double	CGOct [6] = { 0.75, 0.5, 0., 0.1667, 0.0833, 0.1667}
	baryon parameter
double	CGDec [6] = { 0.00, 0.0, 1., 0.3333, 0.6667, 0.3333}
	baryon parameter
double	CGSum [6]
	baryon parameter
int	fMaxIterHad
double	fPrimordialKT
double	fRemnantPT
double	fMinESinglet
double	fWmin
double	fSSBarSuppression
	ssbar suppression
double	fGaussianPt2
	gaussian pt2 distribution width
double	fNonGaussianPt2Tail
	non gaussian pt2 tail parameterization
double	fRemainingECutoff
	remaining E cutoff stopping fragmentation
double	fDiQuarkSuppression
	di-quark suppression parameter
double	fLightVMesonSuppression
	light vector meson suppression
double	fSVMesonSuppression
	strange vector meson suppression
double	fLunda
	Lund a parameter.
double	fLundb
	Lund b parameter.
double	fLundaDiq
	adjustment of Lund a for di-quark

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.
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.
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.
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
int	AddLowRegistry (Registry *rp, bool owns=true)
	add registry with lowest priority, also update ownership
int	MergeTopRegistry (const Registry &r)
int	AddTopRegisties (const vector< Registry * > &rs, bool owns=false)
	Add registries with top priority, also udated Ownerships.
Protected Attributes inherited from genie::Algorithm
bool	fAllowReconfig
bool	fOwnsSubstruc
	true if it owns its substructure (sub-algs,...)
AlgId	fID
	algorithm name and configuration set
vector< Registry * >	fConfVect
vector< bool >	fOwnerships
	ownership for every registry in fConfVect
AlgStatus_t	fStatus
	algorithm execution status
AlgMap *	fOwnedSubAlgMp
	local pool for owned sub-algs (taken out of the factory pool)

Detailed Description

Provides access to the PYTHIA8 hadronization.
.

Author

Alfonso Garcia <aagarciasoto \at km3net.de> IFIC (Valencia)

Created:\n December 12, 2024

License:\n Copyright (c) 2003-2025, The GENIE Collaboration

For the full text of the license visit http://copyright.genie-mc.org or see $GENIE/LICENSE

Definition at line 46 of file LeptoHadPythia8.h.

Constructor & Destructor Documentation

LeptoHadPythia8() [1/2]

LeptoHadPythia8::LeptoHadPythia8

(

)

Definition at line 96 of file LeptoHadPythia8.cxx.

                                 :
EventRecordVisitorI("genie::LeptoHadPythia8")
{
  this->Initialize();
}

References genie::EventRecordVisitorI::EventRecordVisitorI(), and Initialize().

LeptoHadPythia8() [2/2]

LeptoHadPythia8::LeptoHadPythia8

(

string

config

)

Definition at line 102 of file LeptoHadPythia8.cxx.

                                              :
EventRecordVisitorI("genie::LeptoHadPythia8", config)
{
  this->Initialize();
}

References genie::EventRecordVisitorI::EventRecordVisitorI(), and Initialize().

~LeptoHadPythia8()

LeptoHadPythia8::~LeptoHadPythia8 ( )

virtual

Definition at line 108 of file LeptoHadPythia8.cxx.

{
 
}

Member Function Documentation

Configure() [1/2]

void LeptoHadPythia8::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 476 of file LeptoHadPythia8.cxx.

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

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

Configure() [2/2]

void LeptoHadPythia8::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 482 of file LeptoHadPythia8.cxx.

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

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

getBaryon()

int LeptoHadPythia8::getBaryon ( int qq, int q, double rnd ) const

private

create baryon

Definition at line 23 of file LeptoHadPythia8.cxx.

                                                              {
    // options: qq -> dd1=1103 / ud0=2101 / ud1=2103 / uu1=2203 
    // options: q -> d=1 / u=2 / s=3 / c=4 / b=5
    int id1 = qq / 1000;
    int id2 = (qq / 100) % 10;
    int id3 = qq % 10;
    int spin = id3 - 1;
    if (spin==2 && id1!=id2) spin = 4;
    if (q!=id1 && q!=id2) spin++;
    int o1 = TMath::Max( q, TMath::Max( id1, id2) );
    int o3 = TMath::Min( q, TMath::Min( id1, id2) );
    int o2 = q + id1 + id2 - o1 - o3;
    int spinBar = ( CGSum[spin]*rnd<CGOct[spin] ) ? 2 : 4;
    if ( spinBar==2 && o1>o2 && o2>o3 && id3==1 ) return 1000*o1 + 100*o3 + 10*o2 + spinBar; //lambdas
    else                                          return 1000*o1 + 100*o2 + 10*o3 + spinBar;
}

References CGOct, and CGSum.

Referenced by Hadronize().

getMeson()

int LeptoHadPythia8::getMeson ( int q, int qb, double rnd ) const

private

create meson

Definition at line 13 of file LeptoHadPythia8.cxx.

                                                             {
    // options: q -> d=1 / u=1
    // options: qb -> sb=-3 / cb=-4 / bb=-5
    int aqb = abs(qb); 
    int MultipletCode = ( mesonRateSum[aqb-3]*rnd>1 ) ? 1: 3;
    int idMeson = 100*aqb + 10*q + MultipletCode;
    if (qb==-4) return -1*idMeson;
    else        return    idMeson;
}

References mesonRateSum.

Referenced by Hadronize().

getRandomZ()

double LeptoHadPythia8::getRandomZ ( double a, double b ) const

private

fragmentation

Definition at line 40 of file LeptoHadPythia8.cxx.

                                                            {
  // fragmentation function f(x) = ((1-x)^a*exp(-b/x))/x
  // not optimal if a->0 or a->1
  double zpeak = (b+1.-sqrt(pow(b-1.,2)+4.*a*b))/(1.-a)/2.;
  if ( zpeak>0.9999 && b>100. ) zpeak = TMath::Min(zpeak, 1.-a/b);
 
  bool closeto0 = ( zpeak<0.1);
  bool closeto1 = ( zpeak>0.85 && b>1. );
 
  double flw = 1.;
  double fup = 1.;
  double frn = 2.;
  double wdt = 0.5;
 
  if ( closeto0 ) {
    wdt = 2.75*zpeak;
    flw = wdt;
    fup = -wdt*log(wdt);
    frn = flw+fup;
  } 
  else if ( closeto1 ) {
    double rcb = sqrt(4.+pow(1./b,2));
    wdt = rcb - 1./zpeak - (1./b)*log(zpeak*(rcb+1./b)/2. );
    wdt += (a/b)*log(1.-zpeak);
    wdt = TMath::Min(zpeak,TMath::Max(0.,wdt));
    flw = 1./b;
    fup = 1.-wdt;
    frn = flw+fup;
  }
 
  RandomGen * rnd = RandomGen::Instance();
 
  double z,prel,val;  
  while(1){
    z = rnd->RndHadro().Rndm();
    prel = 1.;
    if (closeto0) {
      if ( frn*rnd->RndHadro().Rndm()<flw ) z = wdt*z;
      else { z = pow(wdt,z); prel = wdt/z; }
    } else if (closeto1) {
      if ( frn*rnd->RndHadro().Rndm()<flw) { z = wdt+log(z)/b; prel = exp(b*(z-wdt)); } 
      else z = wdt+(1.-wdt)*z;
    }
    if ( z>0 && z<1 ) {
      double pw = b*(1./zpeak-1./z)+ log(zpeak/z) + a*log((1.-z)/(1.-zpeak));
      val = exp(TMath::Max(-50.,TMath::Min(50.,pw)));
    } 
    else val = 0.;
    if ( val >= rnd->RndHadro().Rndm() * prel) break;
  }
 
  return z;
}

References a, genie::RandomGen::Instance(), and genie::RandomGen::RndHadro().

Referenced by Hadronize().

Hadronize()

bool LeptoHadPythia8::Hadronize ( GHepRecord * event ) const

private

Definition at line 128 of file LeptoHadPythia8.cxx.

{
 
#ifdef __GENIE_PYTHIA8_ENABLED__
  // Compute kinematics of hadronic system with energy/momentum conservation
  LongLorentzVector p4v( * event->Probe()->P4()                   );
  LongLorentzVector p4N( * event->HitNucleon()->P4()              );
  LongLorentzVector p4l( * event->FinalStatePrimaryLepton()->P4() );
  LongLorentzVector p4Hadlong( p4v.Px()+p4N.Px()-p4l.Px(), p4v.Py()+p4N.Py()-p4l.Py(), p4v.Pz()+p4N.Pz()-p4l.Pz(), p4v.E()+p4N.E()-p4l.E() );
 
  LOG("LeptoHad", pDEBUG) << "v [LAB']: " << p4v.E() << " // " << p4v.M2() << " // [ " << p4v.Dx() << " , " << p4v.Dy() << " , " << p4v.Dz() << " ]";
  LOG("LeptoHad", pDEBUG) << "N [LAB']: " << p4N.E() << " // " << p4N.M2() << " // [ " << p4N.Dx() << " , " << p4N.Dy() << " , " << p4N.Dz() << " ]";
  LOG("LeptoHad", pDEBUG) << "l [LAB']: " << p4l.E() << " // " << p4l.M2() << " // [ " << p4l.Dx() << " , " << p4l.Dy() << " , " << p4l.Dz() << " ]";
  LOG("LeptoHad", pDEBUG) << "H [LAB']: " << p4Hadlong.E() << " // " << p4Hadlong.M2() << " // [ " << p4Hadlong.Dx() << " , " << p4Hadlong.Dy() << " , " << p4Hadlong.Dz() << " ]";
 
  // Translate from long double to double
  const TLorentzVector & vtx = *( event->Probe()->X4());
  TLorentzVector p4Had( (double)p4Hadlong.Px(), (double)p4Hadlong.Py(), (double)p4Hadlong.Pz(), (double)p4Hadlong.E() );
  event->AddParticle(kPdgHadronicSyst, kIStDISPreFragmHadronicState, event->HitNucleonPosition(),-1,-1,-1, p4Had, vtx);
 
  const Interaction * interaction = event->Summary();
  interaction->KinePtr()->SetHadSystP4(p4Had);
  interaction->KinePtr()->SetW(p4Hadlong.M());
 
  double W = interaction->Kine().W();
  if(W < fWmin) {
    LOG("LeptoHad", pWARN) << "Low invariant mass, W = " << W << " GeV!!";
    return false;
  }
 
  const XclsTag &      xclstag    = interaction->ExclTag();
  const Target &       target     = interaction->InitState().Tgt();
 
  assert(target.HitQrkIsSet());
 
  bool isp        = pdg::IsProton(target.HitNucPdg());
  int  hit_quark  = target.HitQrkPdg();
  int  frag_quark = xclstag.FinalQuarkPdg();
 
  LOG("LeptoHad", pDEBUG) << "Hit nucleon pdgc = " << target.HitNucPdg() << ", W = " << W;
  LOG("LeptoHad", pDEBUG) << "Selected hit quark pdgc = " << hit_quark << " // Fragmentation quark = " << frag_quark;
 
  RandomGen * rnd = RandomGen::Instance();
 
  //
  // Generate the hadron combination to input PYTHIA
  //
  fPythia->event.reset();
 
  //If the hit quark is a d we have these options:
  /* uud(->q)     => uu + q */
  /* uud d(->q)db => uu + q (d valence and db sea annihilates)*/
  /* udd(->q)     => ud + q */
  /* udd d(->q)db => ud + q (d valence and db sea annihilates)*/
  if ( pdg::IsDQuark(hit_quark) ) {
    // choose diquark system depending on proton or neutron
    int diquark = 0;
    if (isp) diquark = kPdgUUDiquarkS1;
    else     diquark = rnd->RndHadro().Rndm()>0.75 ? kPdgUDDiquarkS1 : kPdgUDDiquarkS0;
    // Check that the trasnferred energy is higher than the mass of the produced quarks
    double m_frag    = PDGLibrary::Instance()->Find(frag_quark)->Mass();
    double m_diquark = PDGLibrary::Instance()->Find(diquark)->Mass();
    if( W <= m_frag + m_diquark + fMinESinglet ) {
      LOG("LeptoHad", pWARN) << "Low invariant mass, W = " << W << " GeV! Returning a null list";
      LOG("LeptoHad", pWARN) << "frag_quark = " << frag_quark << "    -> m = " << m_frag;
      LOG("LeptoHad", pWARN) << "diquark    = " << diquark    << " -> m = "    << m_diquark;
      return 0;
    }
    // Input the two particles to PYTHIA back to back in the CM frame
    double e_frag    = (W*W - m_diquark*m_diquark + m_frag*m_frag)/2./W;
    double e_diquark = (W*W + m_diquark*m_diquark - m_frag*m_frag)/2./W;
    double pz_cm = Pythia8::sqrtpos( e_frag*e_frag - m_frag*m_frag );
    fPythia->event.append(frag_quark, 23, 101, 0, 0., 0.,  pz_cm, e_frag, m_frag);
    fPythia->event.append(diquark,    23, 0, 101, 0., 0., -pz_cm, e_diquark, m_diquark);
  }
 
  //If the hit quark is a u we have these options:
  /* u(->q)ud     => ud + q */
  /* uud u(->q)ub => ud + q (u valence and ub sea annihilates)*/
  /* u(->q)dd     => dd + q */
  /* udd u(->q)ub => dd + q (u valence and ub sea annihilates)*/
  else if ( pdg::IsUQuark(hit_quark) ) {
    // choose diquark system depending on proton or neutron
    int diquark = 0;
    if (isp) diquark = rnd->RndHadro().Rndm()>0.75 ? kPdgUDDiquarkS1 : kPdgUDDiquarkS0;
    else     diquark = kPdgDDDiquarkS1;
    // Check that the trasnferred energy is higher than the mass of the produced quarks.
    double m_frag    = PDGLibrary::Instance()->Find(frag_quark)->Mass();
    double m_diquark = PDGLibrary::Instance()->Find(diquark)->Mass();
    if( W <= m_frag + m_diquark + fMinESinglet ) {
      LOG("LeptoHad", pWARN) << "Low invariant mass, W = " << W << " GeV! Returning a null list";
      LOG("LeptoHad", pWARN) << "frag_quark = " << frag_quark << "    -> m = " << m_frag;
      LOG("LeptoHad", pWARN) << "diquark    = " << diquark    << " -> m = "    << m_diquark;
      return 0;
    }
    // Input the two particles to PYTHIA back to back in the CM frame
    double e_frag    = (W*W - m_diquark*m_diquark + m_frag*m_frag)/2./W;
    double e_diquark = (W*W + m_diquark*m_diquark - m_frag*m_frag)/2./W;
    double pz_cm = Pythia8::sqrtpos( e_frag*e_frag - m_frag*m_frag );
    fPythia->event.append(frag_quark, 23, 101, 0, 0., 0.,  pz_cm, e_frag, m_frag);
    fPythia->event.append(diquark,    23, 0, 101, 0., 0., -pz_cm, e_diquark, m_diquark);
  }
 
 
  // If the hit quark is not u or d then is more complicated.
  // We are using the same procedure use in LEPTO (see lqev.F)
  // Our initial systemt will look like this          ->  qqq + hit_q(->frag_q) + rema_q
  // And we have to input PYTHIA something like this  ->  frag_q + rema  + hadron
  // These are the posible combinations               ->  frag_q[q] + meson [qqb]  + diquark [qq]
  //                                                  ->  frag_q[qb] + baryon [qqq] + quark [q]
  else {
 
    // Remnant of the hit quark (which is from the sea) will be of opposite charge
    int rema_hit_quark = -hit_quark;
 
    // Check that the trasnfered energy is higher than the mass of the produce quarks plus remnant quark and nucleon
    double m_frag     = PDGLibrary::Instance()->Find(frag_quark)->Mass();
    double m_rema_hit = PDGLibrary::Instance()->Find(rema_hit_quark)->Mass();
    if (W <= m_frag + m_rema_hit + 0.9 + fMinESinglet ) {
      LOG("LeptoHad", pWARN) << "Low invariant mass, W = " << W << " GeV! Returning a null list";
      LOG("LeptoHad", pWARN) << " frag_quark     = " << frag_quark     << " -> m = " << m_frag;
      LOG("LeptoHad", pWARN) << " rema_hit_quark = " << rema_hit_quark << " -> m = " << m_rema_hit;
      return 0;
    }
 
    //PDG of the two hadronic particles for the final state
    int hadron = 0;
    int rema   = 0;
 
    int ntwoq = isp ? 2 : 1; //proton two ups & neutron one up
    int counter = 0;
 
    // Here we select the id and kinematics of the hadron and rema particles
    // Some combinations can be kinematically forbiden so we repeat this process
    // up to 100 times before the event is discarded.
    while( counter<fMaxIterHad ) {
 
      // Loop to create a combination of hadron + rema. Two options are possible:
      // 1) diquark [qq] + meson [qqb]
      // 2) quark [q] + baryon [qqq]
      while(hadron==0) {
        //choose a valence quark and the remaining will be a diquark system
        int valquark = int(1.+ntwoq/3.+rnd->RndHadro().Rndm());
        int diquark  = 0;
        if ( valquark==ntwoq ) diquark = rnd->RndHadro().Rndm()>0.75 ? kPdgUDDiquarkS1 : kPdgUDDiquarkS0;
        else                   diquark = 1000*ntwoq+100*ntwoq+3;
 
        // Choose flavours using PYTHIA tool
        if ( rema_hit_quark>0 ) { //create a baryon (qqq)
          hadron = getBaryon(diquark,rema_hit_quark,rnd->RndHadro().Rndm());
          rema = valquark;
        }
        else {                    //create a meson (qqbar)
          hadron = getMeson(valquark,rema_hit_quark,rnd->RndHadro().Rndm());
          rema = diquark;
        }
      }
 
      double m_hadron = PDGLibrary::Instance()->Find(hadron)->Mass();
      double m_rema   = PDGLibrary::Instance()->Find(rema)->Mass();
 
      // Give balancing pT to hadron and rema particles
      double pT  = fRemnantPT * TMath::Sqrt( -1*TMath::Log( rnd->RndHadro().Rndm() ) );
      double pT2 = TMath::Power(pT,2);
      double pr  = TMath::Power(m_hadron,2)+pT2;
      //to generate the longitudinal scaling variable z in jet fragmentation using PYTHIA function
      // Split energy-momentum of remnant using PYTHIA function
      // z=E-pz fraction for rema forming jet-system with frag_q
      // 1-z=E-pz fraction for hadron
      double z = getRandomZ(Afrag,Bfrag*pr);
 
      // Energy of trasnfered to the hadron
      double tm_hadron = pr / z / W;
      double E_hadron   = 0.5 * ( z*W + tm_hadron );  //E_hadron - pz = zW
      double E_pz       = W - tm_hadron;
      double WT         = (1-z) * W * E_pz - pT2;
 
      // Check if energy in jet system is enough for fragmentation.
      if ( WT > TMath::Power(m_frag+m_rema+fMinESinglet,2) ) {
 
        // Energy of transfered to the fragmented quark and rema system
        // Applying energy conservation
        WT = TMath::Sqrt( WT + pT2 );
        double tm_rema   = TMath::Power(m_rema,2) + pT2;
        double E_frag    = 0.5 * ( WT + ( TMath::Power(m_frag,2) - tm_rema)/WT ); //E_frag + E_rema = WT
        double E_rema    = 0.5 * ( WT + (-TMath::Power(m_frag,2) + tm_rema)/WT );
        double x_rema    = -1 * TMath::Sqrt( TMath::Power(E_rema,2) - tm_rema );
        double theta_rema;
        theta_rema = TMath::ATan2(pT,x_rema);
 
        // Select a phi angle between between particles randomly
        double phi = 2*kPi*rnd->RndHadro().Rndm();
 
        double dbez = (E_pz-(1-z)*W)/(E_pz+(1-z)*W);
        double pz_hadron  = -0.5 * ( z*W - tm_hadron );
 
        // Input the three particles to PYTHIA in the CM frame
        // If a top quark is produced we decay it because it does not hadronize
        fPythia->event.append(frag_quark, 23, 101, 0, 0., 0., sqrt(E_frag*E_frag-m_frag*m_frag), E_frag, m_frag);
 
        double p_rema  = sqrt(E_rema*E_rema-m_rema*m_rema);
        fPythia->event.append(rema, 23, 0, 101, p_rema*sin(theta_rema)*sin(phi), p_rema*sin(theta_rema)*cos(phi), p_rema*cos(theta_rema), E_rema, m_rema);
 
        fPythia->event.bst(0,0,dbez);
 
        double theta_hadron = TMath::ATan2(pT,pz_hadron);
 
        double p_hadron = sqrt(E_hadron*E_hadron-m_hadron*m_hadron);
        fPythia->event.append(hadron, 23, 0, 0, p_hadron*sin(theta_hadron)*sin(phi+kPi), p_hadron*sin(theta_hadron)*cos(phi+kPi), p_hadron*cos(theta_hadron), E_hadron, m_hadron);
 
        // Target remnants required to go backwards in hadronic cms
        int nsize = fPythia->event.size();
        if ( fPythia->event[nsize-1].pz()<0 && fPythia->event[nsize-2].pz()<0 ) break; //quit the while( counter<fMaxIterHad )
 
        // break;
 
        LOG("LeptoHad", pINFO) << "Not backward hadron or rema";
        LOG("LeptoHad", pINFO) << "hadron     = " << hadron     << " -> Pz = " << fPythia->event[nsize-1].pz() ;
        LOG("LeptoHad", pINFO) << "rema = " << rema << " -> Pz = " << fPythia->event[nsize-2].pz() ;
        fPythia->event.reset();
        
      }
      else {
        LOG("LeptoHad", pINFO) << "Low WT value ... ";
        LOG("LeptoHad", pINFO) << "WT = " << TMath::Sqrt(WT) << " // m_frag = " << m_frag << " // m_rema = " << m_rema;
      }
 
      LOG("LeptoHad", pINFO) << "Hadronization paricles not suitable. Trying again... " << counter;
      counter++;
      if (counter==100) {
        LOG("LeptoHad", pWARN) << "Hadronization particles failed after " << counter << " iterations! Returning a null list";
        return 0;
      }
 
    }
 
  }
 
  // Introduce a primordial kT system
  double pT  = fPrimordialKT * TMath::Sqrt( -1*TMath::Log( rnd->RndHadro().Rndm() ) );
  double phi   = -2*kPi*rnd->RndHadro().Rndm();
  double theta = 0.;
 
  fPythia->event.rot(theta,phi);
  phi   = -1 * phi;
  theta = TMath::ATan(2.*pT/W);
  fPythia->event.rot(theta,phi);
 
  // fPythia->event.list();
  // fPythia->stat();
 
  // Run PYTHIA with the input particles
  fPythia->next();
  // fPythia->event.list();
  // fPythia->stat();
  Pythia8::Event &fEvent = fPythia->event;
  int np = fEvent.size();
  assert(np>0);
 
  // Boost velocity HCM -> LAB
  long double beta = p4Hadlong.P()/p4Hadlong.E();
 
  //fix numbering for events with top
  bool isTop = false;
 
  //-- Translate the fragmentation products from TMCParticles to
  //   GHepParticles and copy them to the event record.
  int mom = event->FinalStateHadronicSystemPosition();
  assert(mom!=-1);
 
  for (int i = 1; i < np; i++) { // ignore first entry -> (system) pseudoparticle
 
    int pdgc = fEvent[i].id();
    if (!PDGLibrary::Instance()->Find(pdgc)) continue; // some intermediate particles not part of genie tables
 
    int ks   = fEvent[i].status();
 
    // Final state particles can not be quarks or diquarks but colorless
    if(ks > 0) {
      if( pdg::IsQuark(pdgc) || pdg::IsDiQuark(pdgc) ) {
        LOG("LeptoHad", pERROR) << "Hadronization failed! Bare quark/di-quarks appear in final state!";
        return false;
      }
    }
 
    // When top quark is produced, it is immidiately decay before hadronization. Then the decayed
    // products are hadronized with the hadron remnants. Therefore, we remove the top quark from
    // the list of particles so that the mother/daugher assigments is at the same level for decayed
    // products and hadron remnants.
    if ( pdg::IsTQuark( TMath::Abs(pdgc) ) ) { isTop=true; continue; }
 
    // fix numbering scheme used for mother/daughter assignments
    if ( isTop ) {
      (fEvent[i].mother1()==0) ? fEvent[i].mothers(fEvent[i].mother1()-1,fEvent[i].mother2()) : fEvent[i].mothers(fEvent[i].mother1()-2,fEvent[i].mother2());
      fEvent[i].daughters(fEvent[i].daughter1()-2,fEvent[i].daughter2()-2);
    }
    else  {
      fEvent[i].mothers(fEvent[i].mother1()-1,fEvent[i].mother2());
      fEvent[i].daughters(fEvent[i].daughter1()-1,fEvent[i].daughter2()-1);
    }
 
    LongLorentzVector p4long( fEvent[i].px(), fEvent[i].py(), fEvent[i].pz(), fEvent[i].e()  );
    p4long.BoostZ(beta);
    p4long.Rotate(p4Hadlong);
 
    // Translate from long double to double
    TLorentzVector p4( (double)p4long.Px(), (double)p4long.Py(), (double)p4long.Pz(), (double)p4long.E() );
 
    // Somtimes PYTHIA output particles with E smaller than its mass. This is wrong,
    // so we assume that the are at rest.
    double massPDG = PDGLibrary::Instance()->Find(pdgc)->Mass();
    if ( ks>0 && p4.E()<massPDG ) {
      LOG("LeptoHad", pINFO) << "Putting at rest one stable particle generated by PYTHIA because E < m";
      LOG("LeptoHad", pINFO) << "PDG = " << pdgc << " // State = " << ks;
      LOG("LeptoHad", pINFO) << "E = " << p4.E() << " // |p| = " << p4.P();
      LOG("LeptoHad", pINFO) << "p = [ " << p4.Px() << " , "  << p4.Py() << " , "  << p4.Pz() << " ]";
      LOG("LeptoHad", pINFO) << "m    = " << p4.M() << " // mpdg = " << massPDG;
      p4.SetXYZT(0,0,0,massPDG);
    }
 
    // copy final state particles to the event record
    GHepStatus_t ist = (ks>0) ? kIStStableFinalState : kIStDISPreFragmHadronicState;
 
    int im  = mom + 1 + fEvent[i].mother1();
    int ifc = (fEvent[i].daughter1() <= -1) ? -1 : mom + 1 + fEvent[i].daughter1();
    int ilc = (fEvent[i].daughter2()  <= -1) ? -1 : mom + 1 + fEvent[i].daughter2();
 
    double vx = vtx.X() + fEvent[i].xProd()*1e12; //pythia gives position in [mm] while genie uses [fm]
    double vy = vtx.Y() + fEvent[i].yProd()*1e12;
    double vz = vtx.Z() + fEvent[i].zProd()*1e12;
    double vt = vtx.T() + fEvent[i].tProd()*(units::millimeter/units::second);
    TLorentzVector pos( vx, vy, vz, vt );
 
    event->AddParticle( pdgc, ist, im,-1, ifc, ilc, p4, pos );
 
  }
 
  return true;
#else
  return false;
#endif
 
}

References Afrag, Bfrag, genie::utils::math::LongLorentzVector::BoostZ(), genie::utils::math::LongLorentzVector::Dx(), genie::utils::math::LongLorentzVector::Dy(), genie::utils::math::LongLorentzVector::Dz(), genie::utils::math::LongLorentzVector::E(), e, genie::Interaction::ExclTag(), genie::XclsTag::FinalQuarkPdg(), genie::PDGLibrary::Find(), fMaxIterHad, fMinESinglet, fPrimordialKT, fRemnantPT, fWmin, getBaryon(), getMeson(), getRandomZ(), genie::Target::HitNucPdg(), genie::Target::HitQrkIsSet(), genie::Target::HitQrkPdg(), genie::Interaction::InitState(), genie::PDGLibrary::Instance(), genie::RandomGen::Instance(), genie::pdg::IsDiQuark(), genie::pdg::IsDQuark(), genie::pdg::IsProton(), genie::pdg::IsQuark(), genie::pdg::IsTQuark(), genie::pdg::IsUQuark(), genie::Interaction::Kine(), genie::Interaction::KinePtr(), genie::kIStDISPreFragmHadronicState, genie::kIStStableFinalState, genie::kPdgDDDiquarkS1, genie::kPdgHadronicSyst, genie::kPdgUDDiquarkS0, genie::kPdgUDDiquarkS1, genie::kPdgUUDiquarkS1, genie::constants::kPi, LOG, genie::utils::math::LongLorentzVector::M(), genie::utils::math::LongLorentzVector::M2(), genie::units::millimeter, genie::utils::math::LongLorentzVector::P(), pDEBUG, pERROR, pINFO, pWARN, genie::utils::math::LongLorentzVector::Px(), genie::utils::math::LongLorentzVector::Py(), genie::utils::math::LongLorentzVector::Pz(), genie::RandomGen::RndHadro(), genie::utils::math::LongLorentzVector::Rotate(), genie::units::second, genie::Kinematics::SetHadSystP4(), genie::Kinematics::SetW(), genie::InitialState::Tgt(), and genie::Kinematics::W().

Referenced by ProcessEventRecord().

Initialize()

void LeptoHadPythia8::Initialize ( void ) const

private

Definition at line 553 of file LeptoHadPythia8.cxx.

{
 
#ifdef __GENIE_PYTHIA8_ENABLED__
  fPythia = Pythia8Singleton::Instance()->Pythia8();
 
  fPythia->readString("Print:quiet = on");
 
  // sync GENIE and PYTHIA8 seeds
  RandomGen * rnd = RandomGen::Instance();
  long int seed = rnd->GetSeed();
  fPythia->readString("Random:setSeed = on");
  fPythia->settings.mode("Random:seed", seed);
  LOG("LeptoHad", pINFO) << "PYTHIA8  seed = " << fPythia->settings.mode("Random:seed");
 
  //needed to only do hadronization
  fPythia->readString("ProcessLevel:all = off");
#endif
 
}

References genie::RandomGen::GetSeed(), genie::Pythia8Singleton::Instance(), genie::RandomGen::Instance(), LOG, and pINFO.

Referenced by LeptoHadPythia8(), and LeptoHadPythia8().

LoadConfig()

void LeptoHadPythia8::LoadConfig ( void )

private

Definition at line 488 of file LeptoHadPythia8.cxx.

{
 
#ifdef __GENIE_PYTHIA8_ENABLED__
  GetParam("MaxIter-Had", fMaxIterHad ) ;
 
  // Width of Gaussian distribution for transverse momentums
  // Define in LEPTO with PARL(3) and PARL(14)
  GetParam("Primordial-kT", fPrimordialKT ) ;
  GetParam("Remnant-pT",    fRemnantPT ) ;
 
  // It is, with quark masses added, used to define the minimum allowable energy of a colour-singlet parton system.
  GetParam( "Energy-Singlet", fMinESinglet ) ;
 
  GetParam( "Xsec-Wmin", fWmin ) ;
 
  GetParam( "SSBarSuppression",       fSSBarSuppression       );
  GetParam( "GaussianPt2",            fGaussianPt2            );
  GetParam( "NonGaussianPt2Tail",     fNonGaussianPt2Tail     );
  GetParam( "RemainingEnergyCutoff",  fRemainingECutoff       );
  GetParam( "DiQuarkSuppression",     fDiQuarkSuppression     );
  GetParam( "LightVMesonSuppression", fLightVMesonSuppression );
  GetParam( "SVMesonSuppression",     fSVMesonSuppression     );
  GetParam( "Lunda",                  fLunda                  );
  GetParam( "Lundb",                  fLundb                  );
  GetParam( "LundaDiq",               fLundaDiq               );
 
  fPythia->settings.parm("StringFlav:probStoUD",         fSSBarSuppression);
  fPythia->settings.parm("Diffraction:primKTwidth",      fGaussianPt2);
  fPythia->settings.parm("StringPT:enhancedFraction",    fNonGaussianPt2Tail);
  fPythia->settings.parm("StringFragmentation:stopMass", fRemainingECutoff);
  fPythia->settings.parm("StringFlav:probQQtoQ",         fDiQuarkSuppression);
  fPythia->settings.parm("StringFlav:mesonUDvector",     fLightVMesonSuppression);
  fPythia->settings.parm("StringFlav:mesonSvector",      fSVMesonSuppression);
  fPythia->settings.parm("StringZ:aLund",                fLunda);
  fPythia->settings.parm("StringZ:bLund",                fLundb);
  fPythia->settings.parm("StringZ:aExtraDiquark",        fLundaDiq);
 
  // Same default mass of the W boson in pythia8 and genie, so no need to change in pythia8
  // No problem with energy conservation W and top decays, so no need to set the width to 0
 
  Afrag = fPythia->settings.parm("StringZ:aLund");
  Bfrag = fPythia->settings.parm("StringZ:bLund");
 
  bool isAvalid = true;
  if (Afrag<0.02 || abs(Afrag-1)==0.01 ) isAvalid = false;
  if (!isAvalid) {
    LOG("LeptoHad", pFATAL) << "Invalid A factor for fragmenation function" ;
    LOG("LeptoHad", pFATAL) << "A must be (>0.02 & <0.99) | >1.01" ;
    exit(1);
  }
 
  mesonRateSum[0] = 1. + fPythia->settings.parm("StringFlav:mesonSvector"); //0.55 
  mesonRateSum[1] = 1. + fPythia->settings.parm("StringFlav:mesonCvector"); //0.88 
  mesonRateSum[2] = 1. + fPythia->settings.parm("StringFlav:mesonBvector"); //2.20 
 
  double decupletSup = fPythia->settings.parm("StringFlav:decupletSup");;
  for (int i = 0; i < 6; ++i) CGSum[i] = CGOct[i] + decupletSup*CGDec[i];
 
  LOG("LeptoHad", pINFO) << "Initialising PYTHIA..." ;
  fPythia->init(); 
#endif
 
}

References Afrag, Bfrag, CGDec, CGOct, CGSum, fDiQuarkSuppression, fGaussianPt2, fLightVMesonSuppression, fLunda, fLundaDiq, fLundb, fMaxIterHad, fMinESinglet, fNonGaussianPt2Tail, fPrimordialKT, fRemainingECutoff, fRemnantPT, fSSBarSuppression, fSVMesonSuppression, fWmin, genie::Algorithm::GetParam(), LOG, mesonRateSum, pFATAL, and pINFO.

Referenced by Configure(), and Configure().

ProcessEventRecord()

void LeptoHadPythia8::ProcessEventRecord ( GHepRecord * event ) const

virtual

Implements genie::EventRecordVisitorI.

Definition at line 113 of file LeptoHadPythia8.cxx.

{
 
  if(!this->Hadronize(event)) {
    LOG("LeptoHad", pWARN) << "Hadronization failed!";
    event->EventFlags()->SetBitNumber(kHadroSysGenErr, true);
    genie::exceptions::EVGThreadException exception;
    exception.SetReason("Could not simulate the hadronic system");
    exception.SwitchOnFastForward();
    throw exception;
    return;
  }
 
}

References Hadronize(), genie::kHadroSysGenErr, LOG, pWARN, genie::exceptions::EVGThreadException::SetReason(), and genie::exceptions::EVGThreadException::SwitchOnFastForward().

Member Data Documentation

Afrag

double genie::LeptoHadPythia8::Afrag

private

fragmentation parameter

Definition at line 70 of file LeptoHadPythia8.h.

Referenced by Hadronize(), and LoadConfig().

Bfrag

double genie::LeptoHadPythia8::Bfrag

private

fragmentation parameter

Definition at line 71 of file LeptoHadPythia8.h.

Referenced by Hadronize(), and LoadConfig().

CGDec

double genie::LeptoHadPythia8::CGDec[6] = { 0.00, 0.0, 1., 0.3333, 0.6667, 0.3333}

private

baryon parameter

Definition at line 74 of file LeptoHadPythia8.h.

{ 0.00, 0.0, 1., 0.3333, 0.6667, 0.3333};  ///<baryon parameter

Referenced by LoadConfig().

CGOct

double genie::LeptoHadPythia8::CGOct[6] = { 0.75, 0.5, 0., 0.1667, 0.0833, 0.1667}

private

baryon parameter

Definition at line 73 of file LeptoHadPythia8.h.

{ 0.75, 0.5, 0., 0.1667, 0.0833, 0.1667};  ///<baryon parameter

Referenced by getBaryon(), and LoadConfig().

CGSum

double genie::LeptoHadPythia8::CGSum[6]

private

baryon parameter

Definition at line 75 of file LeptoHadPythia8.h.

Referenced by getBaryon(), and LoadConfig().

fDiQuarkSuppression

double genie::LeptoHadPythia8::fDiQuarkSuppression

private

di-quark suppression parameter

Definition at line 89 of file LeptoHadPythia8.h.

Referenced by LoadConfig().

fGaussianPt2

double genie::LeptoHadPythia8::fGaussianPt2

private

gaussian pt2 distribution width

Definition at line 86 of file LeptoHadPythia8.h.

Referenced by LoadConfig().

fLightVMesonSuppression

double genie::LeptoHadPythia8::fLightVMesonSuppression

private

light vector meson suppression

Definition at line 90 of file LeptoHadPythia8.h.

Referenced by LoadConfig().

fLunda

double genie::LeptoHadPythia8::fLunda

private

Lund a parameter.

Definition at line 92 of file LeptoHadPythia8.h.

Referenced by LoadConfig().

fLundaDiq

double genie::LeptoHadPythia8::fLundaDiq

private

adjustment of Lund a for di-quark

Definition at line 94 of file LeptoHadPythia8.h.

Referenced by LoadConfig().

fLundb

double genie::LeptoHadPythia8::fLundb

private

Lund b parameter.

Definition at line 93 of file LeptoHadPythia8.h.

Referenced by LoadConfig().

fMaxIterHad

int genie::LeptoHadPythia8::fMaxIterHad

private

Definition at line 78 of file LeptoHadPythia8.h.

Referenced by Hadronize(), and LoadConfig().

fMinESinglet

double genie::LeptoHadPythia8::fMinESinglet

private

Definition at line 81 of file LeptoHadPythia8.h.

Referenced by Hadronize(), and LoadConfig().

fNonGaussianPt2Tail

double genie::LeptoHadPythia8::fNonGaussianPt2Tail

private

non gaussian pt2 tail parameterization

Definition at line 87 of file LeptoHadPythia8.h.

Referenced by LoadConfig().

fPrimordialKT

double genie::LeptoHadPythia8::fPrimordialKT

private

Definition at line 79 of file LeptoHadPythia8.h.

Referenced by Hadronize(), and LoadConfig().

fRemainingECutoff

double genie::LeptoHadPythia8::fRemainingECutoff

private

remaining E cutoff stopping fragmentation

Definition at line 88 of file LeptoHadPythia8.h.

Referenced by LoadConfig().

fRemnantPT

double genie::LeptoHadPythia8::fRemnantPT

private

Definition at line 80 of file LeptoHadPythia8.h.

Referenced by Hadronize(), and LoadConfig().

fSSBarSuppression

double genie::LeptoHadPythia8::fSSBarSuppression

private

ssbar suppression

Definition at line 85 of file LeptoHadPythia8.h.

Referenced by LoadConfig().

fSVMesonSuppression

double genie::LeptoHadPythia8::fSVMesonSuppression

private

strange vector meson suppression

Definition at line 91 of file LeptoHadPythia8.h.

Referenced by LoadConfig().

fWmin

double genie::LeptoHadPythia8::fWmin

private

Definition at line 82 of file LeptoHadPythia8.h.

Referenced by Hadronize(), and LoadConfig().

mesonRateSum

double genie::LeptoHadPythia8::mesonRateSum[3]

private

meson parameter

Definition at line 72 of file LeptoHadPythia8.h.

Referenced by getMeson(), and LoadConfig().

---

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

• LeptoHadPythia8.h
• LeptoHadPythia8.cxx