G4ExcitedStringDecay.cc

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// Historic fragment from M.Komogorov; clean-up still necessary @@@

#include "G4ExcitedStringDecay.hh"
#include "G4SystemOfUnits.hh"
#include "G4KineticTrack.hh"

G4ExcitedStringDecay::G4ExcitedStringDecay() : G4VStringFragmentation(),
        theStringDecay(0)
{}

G4ExcitedStringDecay::G4ExcitedStringDecay(G4VLongitudinalStringDecay * aStringDecay)
: G4VStringFragmentation(),
  theStringDecay(aStringDecay)
{}

G4ExcitedStringDecay::G4ExcitedStringDecay(const G4ExcitedStringDecay &)
: G4VStringFragmentation(),
  theStringDecay(0)
{
  throw G4HadronicException(__FILE__, __LINE__, "G4ExcitedStringDecay::copy ctor not accessible");
} 

G4ExcitedStringDecay::~G4ExcitedStringDecay()
{
}

const G4ExcitedStringDecay & G4ExcitedStringDecay::operator=(const G4ExcitedStringDecay &)
{
  throw G4HadronicException(__FILE__, __LINE__, "G4ExcitedStringDecay::operator= meant to not be accessable");
  return *this;
}

int G4ExcitedStringDecay::operator==(const G4ExcitedStringDecay &) const
{
  return 0;
}

int G4ExcitedStringDecay::operator!=(const G4ExcitedStringDecay &) const
{
  return 1;
}

G4KineticTrackVector *G4ExcitedStringDecay::FragmentString
                                (const G4ExcitedString &theString)
{
        if ( theStringDecay == NULL ) 

            theStringDecay=new G4LundStringFragmentation();
    
        return theStringDecay->FragmentString(theString);
}
        
G4KineticTrackVector *G4ExcitedStringDecay::FragmentStrings
                                (const G4ExcitedStringVector * theStrings)
{
  G4LorentzVector KTsum(0.,0.,0.,0.);

//G4cout<<"theStrings->size() "<<theStrings->size()<<G4endl;
  for ( unsigned int astring=0; astring < theStrings->size(); astring++)
  {
        KTsum+= theStrings->operator[](astring)->Get4Momentum();
  }

  G4KineticTrackVector * theResult = new G4KineticTrackVector;
  G4int attempts(0);
  G4bool success=false;
  G4bool NeedEnergyCorrector=false;
  do {
       //G4cout<<"Check of momentum at string fragmentations. New try."<<G4endl;
        std::for_each(theResult->begin() , theResult->end() , DeleteKineticTrack());
        theResult->clear();

        attempts++;
        //G4cout<<G4endl<<"attempts "<<attempts<<G4endl;
        G4LorentzVector KTsecondaries(0.,0.,0.,0.);
        NeedEnergyCorrector=false;

        for ( unsigned int astring=0; astring < theStrings->size(); astring++)
        {
          //G4cout<<"String No "<<astring+1<<" "<<theStrings->operator[](astring)->Get4Momentum().mag2()<<" "<<theStrings->operator[](astring)->GetRightParton()->GetPDGcode()<<" "<<theStrings->operator[](astring)->GetLeftParton()->GetPDGcode()<<" "<<theStrings->operator[](astring)->Get4Momentum()<<G4endl;
          //G4int Uzhi; G4cin >>Uzhi;
          G4KineticTrackVector * generatedKineticTracks = NULL;
          if ( theStrings->operator[](astring)->IsExcited() )
          {
           //G4cout<<"Fragment String"<<G4endl;
             generatedKineticTracks=FragmentString(*theStrings->operator[](astring));
          } else {
             generatedKineticTracks = new G4KineticTrackVector;
             generatedKineticTracks->push_back(theStrings->operator[](astring)->GetKineticTrack());
          }    

          if (generatedKineticTracks == NULL) 
          {
             G4cerr << "G4VPartonStringModel:No KineticTracks produced" << G4endl;
             continue;
          }

          G4LorentzVector KTsum1(0.,0.,0.,0.);
          for ( unsigned int aTrack=0; aTrack<generatedKineticTracks->size();aTrack++)
          {
                  //--debug-- G4cout<<"Prod part "<<(*generatedKineticTracks)[aTrack]->GetDefinition()->GetParticleName()<<" "<<(*generatedKineticTracks)[aTrack]->Get4Momentum()<<G4endl;
             theResult->push_back(generatedKineticTracks->operator[](aTrack));
             KTsum1+= (*generatedKineticTracks)[aTrack]->Get4Momentum();
          }
          KTsecondaries+=KTsum1;
        
              //--debug--G4cout << "String secondaries(" <<generatedKineticTracks->size()<< ")  momentum: "
              //--debug--<< theStrings->operator[](astring)->Get4Momentum() << " " << KTsum1 << G4endl;
          if  ( KTsum1.e() > 0 && std::abs((KTsum1.e()-theStrings->operator[](astring)->Get4Momentum().e()) / KTsum1.e()) > perMillion )
          {
                  //--debug--  G4cout << "String secondaries(" <<generatedKineticTracks->size()<< ")  momentum: "
                  //--debug--    << theStrings->operator[](astring)->Get4Momentum() << " " << KTsum1 << G4endl;
            NeedEnergyCorrector=true;
          }

//        clean up
          delete generatedKineticTracks;
        }
       //--debug  G4cout << "Initial Strings / secondaries total  4 momentum " << KTsum << " " <<KTsecondaries << G4endl;

    success=true;
        //G4cout<<"success "<<success<<G4endl;
        if ( NeedEnergyCorrector ) success=EnergyAndMomentumCorrector(theResult, KTsum);
                //G4cout<<"success after Ecorr "<<success<<G4endl;
  } while(!success && (attempts < 10));   // It was 100 !!! Uzhi
                  //G4cout<<"End frag string"<<G4endl;

#ifdef debug_ExcitedStringDecay
  G4LorentzVector  KTsum1=0;
  for ( unsigned int aTrack=0; aTrack<theResult->size();aTrack++)
  {
      G4cout << " corrected tracks .. " << (*theResult)[aTrack]->GetDefinition()->GetParticleName()
      <<"  " << (*theResult)[aTrack]->Get4Momentum() << G4endl;
      KTsum1+= (*theResult)[aTrack]->Get4Momentum();
  }

  G4cout << "Needcorrector/success " << NeedEnergyCorrector << "/" << success << ", Corrected total  4 momentum " << KTsum1  << G4endl;
  if ( ! success ) G4cout << "failed to correct E/p" << G4endl;  
#endif

  return theResult;
}

G4bool G4ExcitedStringDecay::EnergyAndMomentumCorrector
                (G4KineticTrackVector* Output, G4LorentzVector& TotalCollisionMom)   
  {
    const int    nAttemptScale = 500;
    const double ErrLimit = 1.E-5;
    if (Output->empty())
       return TRUE;
    G4LorentzVector SumMom;
    G4double        SumMass = 0;     
    G4double        TotalCollisionMass = TotalCollisionMom.m();

//G4cout<<G4endl<<"EnergyAndMomentumCorrector "<<Output->size()<<G4endl;
    // Calculate sum hadron 4-momenta and summing hadron mass
    unsigned int cHadron;
    for(cHadron = 0; cHadron < Output->size(); cHadron++)
    {
        SumMom  += Output->operator[](cHadron)->Get4Momentum();
        SumMass += Output->operator[](cHadron)->GetDefinition()->GetPDGMass();
    }

//G4cout<<"SumMass TotalCollisionMass "<<SumMass<<" "<<TotalCollisionMass<<G4endl;

    // Cannot correct a single particle
    if (Output->size() < 2) return FALSE;

    if (SumMass > TotalCollisionMass) return FALSE;
    SumMass = SumMom.m2();
    if (SumMass < 0) return FALSE;
    SumMass = std::sqrt(SumMass);

     // Compute c.m.s. hadron velocity and boost KTV to hadron c.m.s.
    G4ThreeVector Beta = -SumMom.boostVector();
    Output->Boost(Beta);

    // Scale total c.m.s. hadron energy (hadron system mass).
    // It should be equal interaction mass
    G4double Scale = 1;
    G4int cAttempt = 0;
    G4double Sum = 0;
    G4bool success = false;
    for(cAttempt = 0; cAttempt < nAttemptScale; cAttempt++)
    {
      Sum = 0;
      for(cHadron = 0; cHadron < Output->size(); cHadron++)
      {
        G4LorentzVector HadronMom = Output->operator[](cHadron)->Get4Momentum();
        HadronMom.setVect(Scale*HadronMom.vect());
        G4double E = std::sqrt(HadronMom.vect().mag2() + sqr(Output->operator[](cHadron)->GetDefinition()->GetPDGMass()));
        HadronMom.setE(E);
        Output->operator[](cHadron)->Set4Momentum(HadronMom);
        Sum += E;
      } 
      Scale = TotalCollisionMass/Sum;    
#ifdef debug_G4ExcitedStringDecay 
      G4cout << "Scale-1=" << Scale -1 
                << ",  TotalCollisionMass=" << TotalCollisionMass
                << ",  Sum=" << Sum
                << G4endl;
#endif     
      if (std::fabs(Scale - 1) <= ErrLimit) 
      {
        success = true;
        break;
      }
    }
#ifdef debug_G4ExcitedStringDecay     
    if(!success)
    {
      G4cout << "G4ExcitedStringDecay::EnergyAndMomentumCorrector - Warning"<<G4endl;
      G4cout << "   Scale not unity at end of iteration loop: "<<TotalCollisionMass<<" "<<Sum<<" "<<Scale<<G4endl;
      G4cout << "   Number of secondaries: " << Output->size() << G4endl;
      G4cout << "   Wanted total energy: " <<  TotalCollisionMom.e() << G4endl; 
      G4cout << "   Increase number of attempts or increase ERRLIMIT"<<G4endl;
//       throw G4HadronicException(__FILE__, __LINE__, "G4ExcitedStringDecay failed to correct...");
    }
#endif     
    // Compute c.m.s. interaction velocity and KTV back boost   
    Beta = TotalCollisionMom.boostVector();
    Output->Boost(Beta);

    return success;
  }