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

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Detailed Description

Definition at line 50 of file G4SingleDiffractiveExcitation.hh.

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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.

{}

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Member Function Documentation

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

Reimplemented from G4QGSDiffractiveExcitation.

Definition at line 59 of file G4SingleDiffractiveExcitation.cc.

References G4UniformRand, G4VSplitableHadron::Get4Momentum(), G4VSplitableHadron::GetDefinition(), G4ParticleDefinition::GetPDGMass(), G4VSplitableHadron::Set4Momentum(), and sqr().

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

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