Added to SVN Repository
This commit is contained in:
paraiso
190
geant4/LEMuSR/G4Modified/G4MuonDecayChannel.cc
Normal file
190
geant4/LEMuSR/G4Modified/G4MuonDecayChannel.cc
Normal file
@ -0,0 +1,190 @@
|
||||
//
|
||||
// ********************************************************************
|
||||
// * DISCLAIMER *
|
||||
// * *
|
||||
// * The following disclaimer summarizes all the specific disclaimers *
|
||||
// * of contributors to this software. The specific disclaimers,which *
|
||||
// * govern, are listed with their locations in: *
|
||||
// * http://cern.ch/geant4/license *
|
||||
// * *
|
||||
// * Neither the authors of this software system, nor their employing *
|
||||
// * institutes,nor the agencies providing financial support for this *
|
||||
// * work make any representation or warranty, express or implied, *
|
||||
// * regarding this software system or assume any liability for its *
|
||||
// * use. *
|
||||
// * *
|
||||
// * 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: G4MuonDecayChannel.cc,v 1.11 2004/12/10 18:02:04 gcosmo Exp $
|
||||
// GEANT4 tag $Name: geant4-07-00-cand-05 $
|
||||
//
|
||||
//
|
||||
// ------------------------------------------------------------
|
||||
// GEANT 4 class header file
|
||||
//
|
||||
// History: first implementation, based on object model of
|
||||
// 30 May 1997 H.Kurashige
|
||||
//
|
||||
// Fix bug in calcuration of electron energy in DecayIt 28 Feb. 01 H.Kurashige
|
||||
// ------------------------------------------------------------
|
||||
|
||||
#include "G4ParticleDefinition.hh"
|
||||
#include "G4DecayProducts.hh"
|
||||
#include "G4VDecayChannel.hh"
|
||||
#include "G4MuonDecayChannel.hh"
|
||||
#include "Randomize.hh"
|
||||
#include "G4LorentzVector.hh"
|
||||
#include "G4LorentzRotation.hh"
|
||||
|
||||
|
||||
G4MuonDecayChannel::G4MuonDecayChannel(const G4String& theParentName,
|
||||
G4double theBR)
|
||||
:G4VDecayChannel("Muon Decay",1)
|
||||
{
|
||||
// set names for daughter particles
|
||||
if (theParentName == "mu+") {
|
||||
SetBR(theBR);
|
||||
SetParent("mu+");
|
||||
SetNumberOfDaughters(3);
|
||||
SetDaughter(0, "e+");
|
||||
SetDaughter(1, "nu_e");
|
||||
SetDaughter(2, "anti_nu_mu");
|
||||
} else if (theParentName == "Mu") {
|
||||
SetBR(theBR);
|
||||
SetParent("Mu");
|
||||
SetNumberOfDaughters(3);
|
||||
SetDaughter(0, "e+");
|
||||
SetDaughter(1, "nu_e");
|
||||
SetDaughter(2, "anti_nu_mu");
|
||||
} else if (theParentName == "mu-") {
|
||||
SetBR(theBR);
|
||||
SetParent("mu-");
|
||||
SetNumberOfDaughters(3);
|
||||
SetDaughter(0, "e-");
|
||||
SetDaughter(1, "anti_nu_e");
|
||||
SetDaughter(2, "nu_mu");
|
||||
} else {
|
||||
#ifdef G4VERBOSE
|
||||
if (GetVerboseLevel()>0) {
|
||||
G4cout << "G4MuonDecayChannel:: constructor :";
|
||||
G4cout << " parent particle is not muon but ";
|
||||
G4cout << theParentName << G4endl;
|
||||
}
|
||||
#endif
|
||||
}
|
||||
}
|
||||
|
||||
G4MuonDecayChannel::~G4MuonDecayChannel()
|
||||
{
|
||||
}
|
||||
|
||||
G4DecayProducts *G4MuonDecayChannel::DecayIt(G4double)
|
||||
{
|
||||
// this version neglects muon polarization
|
||||
// assumes the pure V-A coupling
|
||||
// gives incorrect energy spectrum for neutrinos
|
||||
#ifdef G4VERBOSE
|
||||
if (GetVerboseLevel()>1) G4cout << "G4MuonDecayChannel::DecayIt ";
|
||||
#endif
|
||||
|
||||
if (parent == 0) FillParent();
|
||||
if (daughters == 0) FillDaughters();
|
||||
|
||||
// parent mass
|
||||
G4double parentmass = parent->GetPDGMass();
|
||||
|
||||
//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
|
||||
G4ThreeVector dummy;
|
||||
G4DynamicParticle * parentparticle = new G4DynamicParticle( parent, dummy, 0.0);
|
||||
//create G4Decayproducts
|
||||
G4DecayProducts *products = new G4DecayProducts(*parentparticle);
|
||||
delete parentparticle;
|
||||
|
||||
// calculate daughter momentum
|
||||
G4double daughtermomentum[3];
|
||||
G4double energy;
|
||||
// calcurate electron energy
|
||||
G4double xmax = (1.0+daughtermass[0]*daughtermass[0]/parentmass/parentmass);
|
||||
G4double x;
|
||||
G4double r;
|
||||
do {
|
||||
do {
|
||||
r = G4UniformRand();
|
||||
x = xmax*G4UniformRand();
|
||||
} while (r > (3.0 - 2.0*x)*x*x);
|
||||
energy = x*parentmass/2.0 - daughtermass[0];
|
||||
} while (energy <0.0);
|
||||
//create daughter G4DynamicParticle
|
||||
// daughter 0 (electron)
|
||||
daughtermomentum[0] = std::sqrt(energy*energy + 2.0*energy* daughtermass[0]);
|
||||
G4double costheta, sintheta, phi, sinphi, cosphi;
|
||||
costheta = 2.*G4UniformRand()-1.0;
|
||||
sintheta = std::sqrt((1.0-costheta)*(1.0+costheta));
|
||||
phi = twopi*G4UniformRand()*rad;
|
||||
sinphi = std::sin(phi);
|
||||
cosphi = std::cos(phi);
|
||||
G4ThreeVector direction0(sintheta*cosphi,sintheta*sinphi,costheta);
|
||||
G4DynamicParticle * daughterparticle
|
||||
= new G4DynamicParticle( daughters[0], direction0*daughtermomentum[0]);
|
||||
products->PushProducts(daughterparticle);
|
||||
|
||||
// daughter 1 ,2 (nutrinos)
|
||||
// create neutrinos in the C.M frame of two neutrinos
|
||||
G4double energy2 = parentmass*(1.0 - x/2.0);
|
||||
G4double vmass = std::sqrt((energy2-daughtermomentum[0])*(energy2+daughtermomentum[0]));
|
||||
G4double beta = -1.0*daughtermomentum[0]/energy2;
|
||||
G4double costhetan = 2.*G4UniformRand()-1.0;
|
||||
G4double sinthetan = std::sqrt((1.0-costhetan)*(1.0+costhetan));
|
||||
G4double phin = twopi*G4UniformRand()*rad;
|
||||
G4double sinphin = std::sin(phin);
|
||||
G4double cosphin = std::cos(phin);
|
||||
|
||||
G4ThreeVector direction1(sinthetan*cosphin,sinthetan*sinphin,costhetan);
|
||||
G4DynamicParticle * daughterparticle1
|
||||
= new G4DynamicParticle( daughters[1], direction1*(vmass/2.));
|
||||
G4DynamicParticle * daughterparticle2
|
||||
= new G4DynamicParticle( daughters[2], direction1*(-1.0*vmass/2.));
|
||||
|
||||
// boost to the muon rest frame
|
||||
G4LorentzVector p4;
|
||||
p4 = daughterparticle1->Get4Momentum();
|
||||
p4.boost( direction0.x()*beta, direction0.y()*beta, direction0.z()*beta);
|
||||
daughterparticle1->Set4Momentum(p4);
|
||||
p4 = daughterparticle2->Get4Momentum();
|
||||
p4.boost( direction0.x()*beta, direction0.y()*beta, direction0.z()*beta);
|
||||
daughterparticle2->Set4Momentum(p4);
|
||||
products->PushProducts(daughterparticle1);
|
||||
products->PushProducts(daughterparticle2);
|
||||
daughtermomentum[1] = daughterparticle1->GetTotalMomentum();
|
||||
daughtermomentum[2] = daughterparticle2->GetTotalMomentum();
|
||||
|
||||
// output message
|
||||
#ifdef G4VERBOSE
|
||||
if (GetVerboseLevel()>1) {
|
||||
G4cout << "G4MuonDecayChannel::DecayIt ";
|
||||
G4cout << " create decay products in rest frame " <<G4endl;
|
||||
products->DumpInfo();
|
||||
}
|
||||
#endif
|
||||
return products;
|
||||
}
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Reference in New Issue
Block a user