Gabriele Cosmo
146 lines
5.2 KiB
C++
146 lines
5.2 KiB
C++
//
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// ********************************************************************
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// * DISCLAIMER *
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// * *
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// * The following disclaimer summarizes all the specific disclaimers *
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// * of contributors to this software. The specific disclaimers,which *
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// * govern, are listed with their locations in: *
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// * http://cern.ch/geant4/license *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. *
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// * *
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// * This code implementation is the intellectual property of the *
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// * GEANT4 collaboration. *
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// * By copying, distributing or modifying the Program (or any work *
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// * based on the Program) you indicate your acceptance of this *
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// * statement, and all its terms. *
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// ********************************************************************
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//
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//
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//
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// ------------------------------------------------------------
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// GEANT 4 class implementation file
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//
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// ---------------- G4Parton ----------------
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// by Gunter Folger, June 1998.
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// class for Parton (inside a string) used by Parton String Models
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// ------------------------------------------------------------
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#include "G4Parton.hh"
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#include "G4HadronicException.hh"
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G4Parton::G4Parton(G4int PDGcode)
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{
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PDGencoding=PDGcode;
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theX = 0;
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theDefinition=G4ParticleTable::GetParticleTable()->FindParticle(PDGencoding);
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if (theDefinition == NULL)
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{
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G4cout << "Encoding = "<<PDGencoding<<G4endl;
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G4String text = "G4Parton::GetDefinition(): Encoding not in particle table";
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throw G4HadronicException(__FILE__, __LINE__, text);
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}
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//
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// colour by random in (1,2,3)=(R,G,B) for quarks and
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// in (-1,-2,-3)=(Rbar,Gbar,Bbar) for anti-quarks:
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//
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if (theDefinition->GetParticleType() == "quarks") {
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theColour = ((G4int)(3.*G4UniformRand())+1)*(abs(PDGencoding)/PDGencoding) ;
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}
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//
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// colour by random in (-1,-2,-3)=(Rbar,Gbar,Bbar)=(GB,RB,RG) for di-quarks and
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// in (1,2,3)=(R,G,B)=(GB,RB,RG) for anti-di-quarks:
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//
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else if (theDefinition->GetParticleType() == "diquarks") {
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theColour = -((G4int)(3.*G4UniformRand())+1)*(abs(PDGencoding)/PDGencoding);
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}
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//
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// colour by random in (-11,-12,...,-33)=(RRbar,RGbar,RBbar,...,BBbar) for gluons:
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//
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else if (theDefinition->GetParticleType() == "gluons") {
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theColour = -(((G4int)(3.*G4UniformRand())+1)*10 + ((G4int)(3.*G4UniformRand())+1));
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}
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else {
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G4cout << "Encoding = "<<PDGencoding<<G4endl;
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G4String text = "G4Parton::GetDefinition(): Particle is not a parton";
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throw G4HadronicException(__FILE__, __LINE__, text);
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}
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//
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// isospin-z from PDG-encoded isospin-z for
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// quarks, anti-quarks, di-quarks, and anti-di-quarks:
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//
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if ((theDefinition->GetParticleType() == "quarks") || (theDefinition->GetParticleType() == "diquarks")){
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theIsoSpinZ = theDefinition->GetPDGIsospin3();
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}
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//
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// isospin-z choosen at random from PDG-encoded isospin for gluons (should be zero):
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//
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else {
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G4int thisPDGiIsospin=theDefinition->GetPDGiIsospin();
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if (thisPDGiIsospin == 0) {
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theIsoSpinZ = 0;
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}
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else {
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theIsoSpinZ = ((G4int)((thisPDGiIsospin+1)*G4UniformRand()))-thisPDGiIsospin*0.5;
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}
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}
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//
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// spin-z choosen at random from PDG-encoded spin:
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//
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G4int thisPDGiSpin=theDefinition->GetPDGiSpin();
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if (thisPDGiSpin == 0) {
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theSpinZ = 0;
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}
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else {
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G4int rand=((G4int)((thisPDGiSpin+1)*G4UniformRand()));
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theSpinZ = rand-thisPDGiSpin*0.5;;
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}
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}
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G4Parton::G4Parton(const G4Parton &right)
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{
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PDGencoding = right.PDGencoding;
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theMomentum = right.theMomentum;
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thePosition = right.thePosition;
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theX = right.theX;
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theDefinition = right.theDefinition;
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theColour = right.theColour;
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theIsoSpinZ = right.theIsoSpinZ;
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theSpinZ = right.theSpinZ;
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}
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const G4Parton & G4Parton::operator=(const G4Parton &right)
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{
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PDGencoding=right.GetPDGcode();
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theMomentum=right.Get4Momentum();
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thePosition=right.GetPosition();
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theX = right.theX;
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theDefinition = right.theDefinition;
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theColour = right.theColour;
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theIsoSpinZ = right.theIsoSpinZ;
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theSpinZ = right.theSpinZ;
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return *this;
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}
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G4Parton::~G4Parton()
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{
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// cout << "G4Parton::~G4Parton(): this = "<<this <<endl;
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// cout << "break here"<<this <<endl;
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}
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void G4Parton::DefineMomentumInZ(G4double aLightConeMomentum, G4bool aDirection)
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{
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G4double Mass = GetMass();
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G4LorentzVector a4Momentum = Get4Momentum();
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aLightConeMomentum*=theX;
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G4double TransverseMass2 = sqr(a4Momentum.px()) + sqr(a4Momentum.py()) + sqr(Mass);
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a4Momentum.setPz(0.5*(aLightConeMomentum - TransverseMass2/aLightConeMomentum)*(aDirection? 1: -1));
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a4Momentum.setE( 0.5*(aLightConeMomentum + TransverseMass2/aLightConeMomentum));
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Set4Momentum(a4Momentum);
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}
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