G4SingleDiffractiveExcitation Class Reference

#include <G4SingleDiffractiveExcitation.hh>

Inheritance diagram for G4SingleDiffractiveExcitation:

Public Member Functions
	G4SingleDiffractiveExcitation (G4double sigmaPt=0.6 *CLHEP::GeV, G4double minExtraMass=250 *CLHEP::MeV, G4double x0mass=250 *CLHEP::MeV)
	~G4SingleDiffractiveExcitation ()
G4bool	ExciteParticipants (G4VSplitableHadron *aPartner, G4VSplitableHadron *bPartner) const
Public Member Functions inherited from G4QGSDiffractiveExcitation
	G4QGSDiffractiveExcitation ()
virtual	~G4QGSDiffractiveExcitation ()
virtual G4ExcitedString *	String (G4VSplitableHadron *aHadron, G4bool isProjectile) const

Detailed Description

Definition at line 50 of file G4SingleDiffractiveExcitation.hh.

Constructor & Destructor Documentation

G4SingleDiffractiveExcitation::G4SingleDiffractiveExcitation	(	G4double	sigmaPt = 0.6*CLHEP::GeV,
		G4double	minExtraMass = 250*CLHEP::MeV,
		G4double	x0mass = 250*CLHEP::MeV
	)

Definition at line 49 of file G4SingleDiffractiveExcitation.cc.

:
widthOfPtSquare(-2*sqr(sigmaPt)) , minExtraMass(minextraMass),
minmass(x0mass)
{}

G4SingleDiffractiveExcitation::~G4SingleDiffractiveExcitation

(

)

Definition at line 55 of file G4SingleDiffractiveExcitation.cc.

{}

Member Function Documentation

G4bool G4SingleDiffractiveExcitation::ExciteParticipants ( G4VSplitableHadron *  aPartner, G4VSplitableHadron *  bPartner  ) const

virtual

Reimplemented from G4QGSDiffractiveExcitation.

Definition at line 59 of file G4SingleDiffractiveExcitation.cc.

References CLHEP::HepLorentzVector::boostVector(), G4UniformRand, G4VSplitableHadron::Get4Momentum(), G4VSplitableHadron::GetDefinition(), G4ParticleDefinition::GetPDGMass(), python.hepunit::perCent, CLHEP::HepLorentzVector::rotateY(), CLHEP::HepLorentzVector::rotateZ(), G4VSplitableHadron::Set4Momentum(), CLHEP::HepLorentzVector::setE(), CLHEP::HepLorentzVector::setPz(), sqr(), CLHEP::HepLorentzRotation::transform(), CLHEP::HepLorentzVector::transform(), and CLHEP::HepLorentzVector::vect().

Referenced by G4QGSParticipants::SelectInteractions().

{

    G4LorentzVector Pprojectile=projectile->Get4Momentum();
    G4double Mprojectile2=sqr(projectile->GetDefinition()->GetPDGMass() + minExtraMass);

    G4LorentzVector Ptarget=target->Get4Momentum();
    G4double Mtarget2=sqr(target->GetDefinition()->GetPDGMass() + minExtraMass);
    //       G4cout << "E proj, target :" << Pprojectile.e() << ", " <<
    //                      Ptarget.e() << G4endl;

    G4bool KeepProjectile= G4UniformRand() > 0.5;

    //     reset the min.mass of the non diffractive particle to its value, ( minus a bit for rounding...)
    if ( KeepProjectile )
    {
        //      cout << " Projectile fix" << G4endl;
        Mprojectile2 = sqr(projectile->GetDefinition()->GetPDGMass() * (1-perCent) );
    } else {
        //      cout << " Target fix" << G4endl;
        Mtarget2=sqr(target->GetDefinition()->GetPDGMass() * (1-perCent) );
    }

    // Transform momenta to cms and then rotate parallel to z axis;

    G4LorentzVector Psum;
    Psum=Pprojectile+Ptarget;

    G4LorentzRotation toCms(-1*Psum.boostVector());

    G4LorentzVector Ptmp=toCms*Pprojectile;

    if ( Ptmp.pz() <= 0. )
    {
        // "String" moving backwards in  CMS, abort collision !!
        //         G4cout << " abort Collision!! " << G4endl;
        return false;
    }

    toCms.rotateZ(-1*Ptmp.phi());
    toCms.rotateY(-1*Ptmp.theta());

    //     G4cout << "Pprojectile  be4 boost " << Pprojectile << G4endl;
    //     G4cout << "Ptarget be4 boost : " << Ptarget << G4endl;



    G4LorentzRotation toLab(toCms.inverse());

    Pprojectile.transform(toCms);
    Ptarget.transform(toCms);

    G4LorentzVector Qmomentum;
    G4int whilecount=0;
    do {
        //  Generate pt

        G4double maxPtSquare=sqr(Ptarget.pz());
        if (whilecount++ >= 500 && (whilecount%100)==0)
            //       G4cout << "G4SingleDiffractiveExcitation::ExciteParticipants possibly looping"
            //       << ", loop count/ maxPtSquare : "
            //               << whilecount << " / " << maxPtSquare << G4endl;
            if (whilecount > 1000 )
            {
                Qmomentum=G4LorentzVector(0.,0.,0.,0.);
                //       G4cout << "G4SingleDiffractiveExcitation::ExciteParticipants: Aborting loop!" << G4endl;
                return false;     //  Ignore this interaction
            }
        Qmomentum=G4LorentzVector(GaussianPt(widthOfPtSquare,maxPtSquare),0);


        //  Momentum transfer
        G4double Xmin = minmass / ( Pprojectile.e() + Ptarget.e() );
        G4double Xmax=1.;
        G4double Xplus =ChooseX(Xmin,Xmax);
        G4double Xminus=ChooseX(Xmin,Xmax);

        G4double pt2=G4ThreeVector(Qmomentum.vect()).mag2();
        G4double Qplus =-1 * pt2 / Xminus/Ptarget.minus();
        G4double Qminus=     pt2 / Xplus /Pprojectile.plus();

        if ( KeepProjectile )
        {
            Qminus = (sqr(projectile->GetDefinition()->GetPDGMass()) + pt2 )
                            / (Pprojectile.plus() + Qplus )
                            -  Pprojectile.minus();
        } else
        {
            Qplus = Ptarget.plus()
                          - (sqr(target->GetDefinition()->GetPDGMass()) + pt2 )
                          / (Ptarget.minus() - Qminus );
        }           

        Qmomentum.setPz( (Qplus-Qminus)/2 );
        Qmomentum.setE(  (Qplus+Qminus)/2 );

        //   G4cout << "Qplus / Qminus " << Qplus << " / " << Qminus<<G4endl;
        //   G4cout << "pt2 " << pt2 << G4endl;
        //   G4cout << "Qmomentum " << Qmomentum << G4endl;
        //   G4cout << " Masses (P/T) : " << (Pprojectile+Qmomentum).mag() <<
        //             " / " << (Ptarget-Qmomentum).mag() << G4endl;

    } while (  (Ptarget-Qmomentum).mag2() <= Mtarget2
            || (Pprojectile+Qmomentum).mag2() <= Mprojectile2
            || (Ptarget-Qmomentum).e() < 0.
            || (Pprojectile+Qmomentum).e() < 0. );


    //     G4double Ecms=Pprojectile.e() + Ptarget.e();

    Pprojectile += Qmomentum;

    Ptarget     -= Qmomentum;

    //     G4cout << "Pprojectile.e()  : " << Pprojectile.e() << G4endl;
    //     G4cout << "Ptarget.e()      : " << Ptarget.e() << G4endl;

    //     G4cout << "end event_______________________________________________"<<G4endl;
    //


    //     G4cout << "Pprojectile with Q : " << Pprojectile << G4endl;
    //     G4cout << "Ptarget with Q : " << Ptarget << G4endl;
    //     G4cout << "Projectile back: " << toLab * Pprojectile << G4endl;
    //     G4cout << "Target back: " << toLab * Ptarget << G4endl;

    // Transform back and update SplitableHadron Participant.
    Pprojectile.transform(toLab);
    Ptarget.transform(toLab);

    //     G4cout << "G4SingleDiffractiveExcitation- Target mass      " <<  Ptarget.mag() << G4endl;
    //     G4cout << "G4SingleDiffractiveExcitation- Projectile mass  " <<  Pprojectile.mag() << G4endl;

    target->Set4Momentum(Ptarget);
    projectile->Set4Momentum(Pprojectile);


    return true;
}

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

• G4SingleDiffractiveExcitation.hh
• G4SingleDiffractiveExcitation.cc