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103bda00c8680bda1a926bc1a7b4fd8ebc9b2d72
geant4/source/processes/hadronic/models/generator/util/src/G4GeneralPhaseSpaceDecay.cc
T
Gabriele Cosmo 103bda00c8 Import Geant4 1.1.0 source tree
2016-06-08 15:34:16 +02:00

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// This code implementation is the intellectual property of
// the GEANT4 collaboration.
//
// By copying, distributing or modifying the Program (or any work
// based on the Program) you indicate your acceptance of this statement,
// and all its terms.
//
// $Id: G4GeneralPhaseSpaceDecay.cc,v 1.1.10.1.2.1 1999/12/08 17:34:44 gunter Exp $
// GEANT4 tag $Name: geant4-01-01 $
//
// $Id: G4GeneralSpaceDecay.cc,v 1.0 1998/05/21
// ----------------------------------------------------------------
// GEANT 4 class header file
//
// For information related to this code contact:
// CERN, CN Division, ASD Group
// History: first implementation, A. Feliciello, 21st May 1998
//
// Note: this class is a generalization of the
// G4PhaseSpaceDecayChannel one
// ----------------------------------------------------------------
#include "G4ParticleDefinition.hh"
#include "G4DecayProducts.hh"
#include "G4VDecayChannel.hh"
#include "G4GeneralPhaseSpaceDecay.hh"
#include "Randomize.hh"
#include "G4LorentzVector.hh"
#include "G4LorentzRotation.hh"
#include "G4ios.hh"
G4GeneralPhaseSpaceDecay::G4GeneralPhaseSpaceDecay(G4int Verbose) :
G4VDecayChannel("Phase Space", Verbose)
{
if (GetVerboseLevel()>1) G4cout << "G4GeneralPhaseSpaceDecay:: constructor " << G4endl;
}
G4GeneralPhaseSpaceDecay::G4GeneralPhaseSpaceDecay(const G4String& theParentName,
G4double theBR,
G4int theNumberOfDaughters,
const G4String& theDaughterName1,
const G4String& theDaughterName2,
const G4String& theDaughterName3) :
G4VDecayChannel("Phase Space",
theParentName,theBR,
theNumberOfDaughters,
theDaughterName1,
theDaughterName2,
theDaughterName3)
{
if (GetVerboseLevel()>1) G4cout << "G4GeneralPhaseSpaceDecay:: constructor " << G4endl;
// Set the parent particle (resonance) mass to the (default) PDG vale
if (parent != NULL)
{
parentmass = parent->GetPDGMass();
}
}
G4GeneralPhaseSpaceDecay::G4GeneralPhaseSpaceDecay(const G4String& theParentName,
G4double theParentMass,
G4double theBR,
G4int theNumberOfDaughters,
const G4String& theDaughterName1,
const G4String& theDaughterName2,
const G4String& theDaughterName3) :
parentmass(theParentMass),
G4VDecayChannel("Phase Space",
theParentName,theBR,
theNumberOfDaughters,
theDaughterName1,
theDaughterName2,
theDaughterName3)
{
if (GetVerboseLevel()>1) G4cout << "G4GeneralPhaseSpaceDecay:: constructor " << G4endl;
}
G4GeneralPhaseSpaceDecay::~G4GeneralPhaseSpaceDecay()
{
}
G4DecayProducts *G4GeneralPhaseSpaceDecay::DecayIt(G4double)
{
if (GetVerboseLevel()>1) G4cout << "G4GeneralPhaseSpaceDecay::DecayIt ";
G4DecayProducts * products = NULL;
if (parent == NULL) FillParent();
if (daughters == NULL) FillDaughters();
switch (numberOfDaughters){
case 0:
if (GetVerboseLevel()>0) {
G4cout << "G4GeneralPhaseSpaceDecay::DecayIt ";
G4cout << " daughters not defined " <<G4endl;
}
break;
case 1:
products = OneBodyDecayIt();
break;
case 2:
products = TwoBodyDecayIt();
break;
case 3:
products = ThreeBodyDecayIt();
break;
default:
products = ManyBodyDecayIt();
break;
}
if ((products == NULL) && (GetVerboseLevel()>0)) {
G4cout << "G4GeneralPhaseSpaceDecay::DecayIt ";
G4cout << *parent_name << " can not decay " << G4endl;
DumpInfo();
}
return products;
}
G4DecayProducts *G4GeneralPhaseSpaceDecay::OneBodyDecayIt()
{
if (GetVerboseLevel()>1) G4cout << "G4GeneralPhaseSpaceDecay::OneBodyDecayIt()"<<G4endl;
G4double daughtermass = daughters[0]->GetPDGMass();
//create parent G4DynamicParticle at rest
G4ParticleMomentum dummy;
G4DynamicParticle * parentparticle = new G4DynamicParticle(parent, dummy, 0.0);
//create G4Decayproducts
G4DecayProducts *products = new G4DecayProducts(*parentparticle);
delete parentparticle;
//create daughter G4DynamicParticle at rest
G4DynamicParticle * daughterparticle = new G4DynamicParticle(daughters[0], dummy, 0.0);
products->PushProducts(daughterparticle);
if (GetVerboseLevel()>1)
{
G4cout << "G4GeneralPhaseSpaceDecay::OneBodyDecayIt ";
G4cout << " create decay products in rest frame " <<G4endl;
products->DumpInfo();
}
return products;
}
G4DecayProducts *G4GeneralPhaseSpaceDecay::TwoBodyDecayIt()
{
if (GetVerboseLevel()>1) G4cout << "G4GeneralPhaseSpaceDecay::TwoBodyDecayIt()"<<G4endl;
//daughters'mass
G4double daughtermass[2];
G4double daughtermomentum;
daughtermass[0] = daughters[0]->GetPDGMass();
daughtermass[1] = daughters[1]->GetPDGMass();
G4double sumofdaughtermass = daughtermass[0] + daughtermass[1];
//create parent G4DynamicParticle at rest
G4ParticleMomentum dummy;
G4DynamicParticle * parentparticle = new G4DynamicParticle( parent, dummy, 0.0);
//create G4Decayproducts
G4DecayProducts *products = new G4DecayProducts(*parentparticle);
delete parentparticle;
//calculate daughter momentum
daughtermomentum = Pmx(parentmass,daughtermass[0],daughtermass[1]);
G4double costheta = 2.*G4UniformRand()-1.0;
G4double sintheta = sqrt((1.0 - costheta)*(1.0 + costheta));
G4double phi = 2.0*M_PI*G4UniformRand()*rad;
G4ParticleMomentum direction(sintheta*cos(phi),sintheta*sin(phi),costheta);
//create daughter G4DynamicParticle
G4DynamicParticle * daughterparticle = new G4DynamicParticle( daughters[0], direction*daughtermomentum);
products->PushProducts(daughterparticle);
daughterparticle = new G4DynamicParticle( daughters[1], direction*(-1.0*daughtermomentum));
products->PushProducts(daughterparticle);
if (GetVerboseLevel()>1)
{
G4cout << "G4GeneralPhaseSpaceDecay::TwoBodyDecayIt ";
G4cout << " create decay products in rest frame " <<G4endl;
products->DumpInfo();
}
return products;
}
G4DecayProducts *G4GeneralPhaseSpaceDecay::ThreeBodyDecayIt()
// algorism of this code is originally written in GDECA3 of GEANT3
{
if (GetVerboseLevel()>1) G4cout << "G4GeneralPhaseSpaceDecay::ThreeBodyDecayIt()"<<G4endl;
//daughters'mass
G4double daughtermass[3];
G4double sumofdaughtermass = 0.0;
for (G4int index=0; index<3; index++)
{
daughtermass[index] = daughters[index]->GetPDGMass();
sumofdaughtermass += daughtermass[index];
}
//create parent G4DynamicParticle at rest
G4ParticleMomentum dummy;
G4DynamicParticle * parentparticle = new G4DynamicParticle( parent, dummy, 0.0);
//create G4Decayproducts
G4DecayProducts *products = new G4DecayProducts(*parentparticle);
delete parentparticle;
//calculate daughter momentum
// Generate two
G4double rd1, rd2, rd;
G4double daughtermomentum[3];
G4double momentummax=0.0, momentumsum = 0.0;
G4double energy;
do
{
rd1 = G4UniformRand();
rd2 = G4UniformRand();
if (rd2 > rd1)
{
rd = rd1;
rd1 = rd2;
rd2 = rd;
}
momentummax = 0.0;
momentumsum = 0.0;
// daughter 0
energy = rd2*(parentmass - sumofdaughtermass);
daughtermomentum[0] = sqrt(energy*energy + 2.0*energy* daughtermass[0]);
if ( daughtermomentum[0] >momentummax )momentummax = daughtermomentum[0];
momentumsum += daughtermomentum[0];
// daughter 1
energy = (1.-rd1)*(parentmass - sumofdaughtermass);
daughtermomentum[1] = sqrt(energy*energy + 2.0*energy* daughtermass[1]);
if ( daughtermomentum[1] >momentummax )momentummax = daughtermomentum[1];
momentumsum += daughtermomentum[1];
// daughter 2
energy = (rd1-rd2)*(parentmass - sumofdaughtermass);
daughtermomentum[2] = sqrt(energy*energy + 2.0*energy* daughtermass[2]);
if ( daughtermomentum[2] >momentummax )momentummax = daughtermomentum[2];
momentumsum += daughtermomentum[2];
} while (momentummax > momentumsum - momentummax );
// output message
if (GetVerboseLevel()>1) {
G4cout << " daughter 0:" << daughtermomentum[0]/GeV << "[GeV/c]" <<G4endl;
G4cout << " daughter 1:" << daughtermomentum[1]/GeV << "[GeV/c]" <<G4endl;
G4cout << " daughter 2:" << daughtermomentum[2]/GeV << "[GeV/c]" <<G4endl;
G4cout << " momentum sum:" << momentumsum/GeV << "[GeV/c]" <<G4endl;
}
//create daughter G4DynamicParticle
G4double costheta, sintheta, phi, sinphi, cosphi;
G4double costhetan, sinthetan, phin, sinphin, cosphin;
costheta = 2.*G4UniformRand()-1.0;
sintheta = sqrt((1.0-costheta)*(1.0+costheta));
phi = 2.0*M_PI*G4UniformRand()*rad;
sinphi = sin(phi);
cosphi = cos(phi);
G4ParticleMomentum direction0(sintheta*cosphi,sintheta*sinphi,costheta);
G4DynamicParticle * daughterparticle
= new G4DynamicParticle( daughters[0], direction0*daughtermomentum[0]);
products->PushProducts(daughterparticle);
costhetan = (daughtermomentum[1]*daughtermomentum[1]-daughtermomentum[2]*daughtermomentum[2]-daughtermomentum[0]*daughtermomentum[0])/(2.0*daughtermomentum[2]*daughtermomentum[0]);
sinthetan = sqrt((1.0-costhetan)*(1.0+costhetan));
phin = 2.0*M_PI*G4UniformRand()*rad;
sinphin = sin(phin);
cosphin = cos(phin);
G4ParticleMomentum direction2;
direction2.setX( sinthetan*cosphin*costheta*cosphi - sinthetan*sinphin*sinphi + costhetan*sintheta*cosphi);
direction2.setY( sinthetan*cosphin*costheta*sinphi + sinthetan*sinphin*cosphi + costhetan*sintheta*sinphi);
direction2.setZ( -sinthetan*cosphin*sintheta + costhetan*costheta);
daughterparticle = new G4DynamicParticle( daughters[2], direction2*(daughtermomentum[2]/direction2.mag()));
products->PushProducts(daughterparticle);
daughterparticle =
new G4DynamicParticle(
daughters[1],
(direction0*daughtermomentum[0] + direction2*(daughtermomentum[2]/direction2.mag()))*(-1.0)
);
products->PushProducts(daughterparticle);
if (GetVerboseLevel()>1) {
G4cout << "G4GeneralPhaseSpaceDecay::ThreeBodyDecayIt ";
G4cout << " create decay products in rest frame " <<G4endl;
products->DumpInfo();
}
return products;
}
G4DecayProducts *G4GeneralPhaseSpaceDecay::ManyBodyDecayIt()
// algorism of this code is originally written in FORTRAN by M.Asai
//*****************************************************************
// NBODY
// N-body phase space Monte-Carlo generator
// Makoto Asai
// Hiroshima Institute of Technology
// (asai@kekvax.kek.jp)
// Revised release : 19/Apr/1995
//
{
//return value
G4DecayProducts *products;
if (GetVerboseLevel()>1) G4cout << "G4GeneralPhaseSpaceDecay::ManyBodyDecayIt()"<<G4endl;
//daughters'mass
G4double *daughtermass = new G4double[numberOfDaughters];
G4double sumofdaughtermass = 0.0;
for (G4int index=0; index<numberOfDaughters; index++){
daughtermass[index] = daughters[index]->GetPDGMass();
sumofdaughtermass += daughtermass[index];
}
//Calculate daughter momentum
G4double *daughtermomentum = new G4double[numberOfDaughters];
G4ParticleMomentum direction;
G4DynamicParticle **daughterparticle;
G4double *sm = new G4double[numberOfDaughters];
G4double tmas;
G4double weight = 1.0;
G4int numberOfTry = 0;
G4int index1, index2;
do {
//Generate rundom number in descending order
G4double temp;
G4double *rd = new G4double[numberOfDaughters];
rd[0] = 1.0;
for(index1 =1; index1 < numberOfDaughters -1; index1++)
rd[index1] = G4UniformRand();
rd[ numberOfDaughters -1] = 0.0;
for(index1 =1; index1 < numberOfDaughters -1; index1++) {
for(index2 = index1+1; index2 < numberOfDaughters; index2++) {
if (rd[index1] < rd[index2]){
temp = rd[index1];
rd[index1] = rd[index2];
rd[index2] = temp;
}
}
}
//calcurate virtual mass
tmas = parentmass - sumofdaughtermass;
temp = sumofdaughtermass;
for(index1 =0; index1 < numberOfDaughters; index1++) {
sm[index1] = rd[index1]*tmas + temp;
temp -= daughtermass[index1];
if (GetVerboseLevel()>1) {
G4cout << index1 << " rundom number:" << rd[index1];
G4cout << " virtual mass:" << sm[index1]/GeV << "[GeV/c/c]" <<G4endl;
}
}
delete [] rd;
//Calculate daughter momentum
weight = 1.0;
index1 =numberOfDaughters-1;
daughtermomentum[index1]= Pmx( sm[index1-1],daughtermass[index1-1],sm[index1]);
if (GetVerboseLevel()>1) {
G4cout << " daughter " << index1 << ":" << *daughters_name[index1];
G4cout << " momentum:" << daughtermomentum[index1]/GeV << "[GeV/c]" <<G4endl;
}
for(index1 =numberOfDaughters-2; index1>=0; index1--) {
// calculate
daughtermomentum[index1]= Pmx( sm[index1],daughtermass[index1], sm[index1 +1]);
if(daughtermomentum[index1] < 0.0) {
// !!! illegal momentum !!!
if (GetVerboseLevel()>0) {
G4cout << "G4GeneralPhaseSpaceDecay::ManyBodyDecayIt ";
G4cout << " can not calculate daughter momentum " <<G4endl;
G4cout << " parent:" << *parent_name;
G4cout << " mass:" << parentmass/GeV << "[GeV/c/c]" <<G4endl;
G4cout << " daughter " << index1 << ":" << *daughters_name[index1];
G4cout << " mass:" << daughtermass[index1]/GeV << "[GeV/c/c]" ;
G4cout << " mass:" << daughtermomentum[index1]/GeV << "[GeV/c]" <<G4endl;
}
delete [] sm;
delete [] daughtermass;
delete [] daughtermomentum;
return NULL; // Error detection
} else {
// calculate weight of this events
weight *= daughtermomentum[index1]/sm[index1];
if (GetVerboseLevel()>1) {
G4cout << " daughter " << index1 << ":" << *daughters_name[index1];
G4cout << " momentum:" << daughtermomentum[index1]/GeV << "[GeV/c]" <<G4endl;
}
}
}
if (GetVerboseLevel()>1) {
G4cout << " weight: " << weight <<G4endl;
}
// exit if number of Try exceeds 100
if (numberOfTry++ >100) {
if (GetVerboseLevel()>0) {
G4cout << "G4GeneralPhaseSpaceDecay::ManyBodyDecayIt: ";
G4cout << " can not determine Decay Kinematics " << G4endl;
}
delete [] sm;
delete [] daughtermass;
delete [] daughtermomentum;
return NULL; // Error detection
}
} while ( weight > G4UniformRand());
if (GetVerboseLevel()>1) {
G4cout << "Start calulation of daughters momentum vector "<<G4endl;
}
G4double costheta, sintheta, phi;
G4double beta;
daughterparticle = new G4DynamicParticle*[numberOfDaughters];
index1 = numberOfDaughters -2;
costheta = 2.*G4UniformRand()-1.0;
sintheta = sqrt((1.0-costheta)*(1.0+costheta));
phi = 2.0*M_PI*G4UniformRand()*rad;
direction.setZ(costheta);
direction.setY(sintheta*sin(phi));
direction.setX(sintheta*cos(phi));
daughterparticle[index1] = new G4DynamicParticle( daughters[index1], direction*daughtermomentum[index1] );
daughterparticle[index1+1] = new G4DynamicParticle( daughters[index1+1], direction*(-1.0*daughtermomentum[index1]) );
for (index1 = numberOfDaughters -3; index1 >= 0; index1--) {
//calculate momentum direction
costheta = 2.*G4UniformRand()-1.0;
sintheta = sqrt((1.0-costheta)*(1.0+costheta));
phi = 2.0*M_PI*G4UniformRand()*rad;
direction.setZ(costheta);
direction.setY(sintheta*sin(phi));
direction.setX(sintheta*cos(phi));
// boost already created particles
beta = daughtermomentum[index1];
beta /= sqrt( daughtermomentum[index1]*daughtermomentum[index1] + sm[index1+1]*sm[index1+1] );
for (G4int index2 = index1+1; index2<numberOfDaughters; index2++) {
G4LorentzVector p4;
// make G4LorentzVector for secondaries
p4 = daughterparticle[index2]->Get4Momentum();
// boost secondaries to new frame
p4.boost( direction.x()*beta, direction.y()*beta, direction.z()*beta);
// change energy/momentum
daughterparticle[index2]->Set4Momentum(p4);
}
//create daughter G4DynamicParticle
daughterparticle[index1]= new G4DynamicParticle( daughters[index1], direction*(-1.0*daughtermomentum[index1]));
}
//create G4Decayproducts
G4DynamicParticle *parentparticle;
direction.setX(1.0); direction.setY(0.0); direction.setZ(0.0);
parentparticle = new G4DynamicParticle( parent, direction, 0.0);
products = new G4DecayProducts(*parentparticle);
delete parentparticle;
for (index1 = 0; index1<numberOfDaughters; index1++) {
products->PushProducts(daughterparticle[index1]);
}
if (GetVerboseLevel()>1) {
G4cout << "G4GeneralPhaseSpaceDecay::ManyBodyDecayIt ";
G4cout << " create decay products in rest frame " << G4endl;
products->DumpInfo();
}
delete [] daughterparticle;
delete [] daughtermomentum;
delete [] daughtermass;
delete [] sm;
return products;
}
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