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This commit is contained in:
Gabriele Cosmo
2023-12-08 10:43:34 +01:00
parent dd1f179cda
commit 860a2b92bf
3962 changed files with 139318 additions and 164259 deletions
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source/particles/management/src/G4MuonDecayChannelWithSpin.cc
+91 -107
View File
@@ -31,30 +31,26 @@
// 187-248. North-Holland Publishing Company, Amsterdam at page 210 cc.
// - W.E. Fisher and F. Scheck, Nucl. Phys. B83 (1974) 25.
// Authors: P.Gumplinger and T.MacPhail, 17 August 2004
// Authors: P.Gumplinger and T.MacPhail, 17 August 2004
// --------------------------------------------------------------------
#include "G4MuonDecayChannelWithSpin.hh"
#include "G4DecayProducts.hh"
#include "G4LorentzVector.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "Randomize.hh"
#include "G4DecayProducts.hh"
#include "G4LorentzVector.hh"
G4MuonDecayChannelWithSpin::G4MuonDecayChannelWithSpin(const G4String& theParentName,
G4double theBR)
: G4MuonDecayChannel(theParentName, theBR)
{}
G4MuonDecayChannelWithSpin::
G4MuonDecayChannelWithSpin(const G4String& theParentName,
G4double theBR)
: G4MuonDecayChannel(theParentName,theBR)
G4MuonDecayChannelWithSpin&
G4MuonDecayChannelWithSpin::operator=(const G4MuonDecayChannelWithSpin& right)
{
}
G4MuonDecayChannelWithSpin& G4MuonDecayChannelWithSpin::
operator=(const G4MuonDecayChannelWithSpin& right)
{
if (this != &right)
{
if (this != &right) {
kinematics_name = right.kinematics_name;
verboseLevel = right.verboseLevel;
rbranch = right.rbranch;
@@ -68,12 +64,10 @@ operator=(const G4MuonDecayChannelWithSpin& right)
// recreate array
numberOfDaughters = right.numberOfDaughters;
if ( numberOfDaughters > 0 )
{
if (numberOfDaughters > 0) {
daughters_name = new G4String*[numberOfDaughters];
// copy daughters name
for (G4int index=0; index<numberOfDaughters; ++index)
{
for (G4int index = 0; index < numberOfDaughters; ++index) {
daughters_name[index] = new G4String(*right.daughters_name[index]);
}
}
@@ -81,14 +75,14 @@ operator=(const G4MuonDecayChannelWithSpin& right)
return *this;
}
G4DecayProducts* G4MuonDecayChannelWithSpin::DecayIt(G4double)
G4DecayProducts* G4MuonDecayChannelWithSpin::DecayIt(G4double)
{
// This version assumes V-A coupling with 1st order radiative correctons,
// the standard model Michel parameter values, but
// gives incorrect energy spectrum for neutrinos
#ifdef G4VERBOSE
if (GetVerboseLevel()>1) G4cout << "G4MuonDecayChannelWithSpin::DecayIt ";
if (GetVerboseLevel() > 1) G4cout << "G4MuonDecayChannelWithSpin::DecayIt ";
#endif
CheckAndFillParent();
@@ -99,42 +93,40 @@ G4DecayProducts* G4MuonDecayChannelWithSpin::DecayIt(G4double)
G4double EMMU = parentmass;
//daughters'mass
G4double daughtermass[3];
//G4double sumofdaughtermass = 0.0;
for (G4int index=0; index<3; ++index)
{
// daughters'mass
G4double daughtermass[3];
// G4double sumofdaughtermass = 0.0;
for (G4int index = 0; index < 3; ++index) {
daughtermass[index] = G4MT_daughters[index]->GetPDGMass();
//sumofdaughtermass += daughtermass[index];
// sumofdaughtermass += daughtermass[index];
}
G4double EMASS = daughtermass[0];
// create parent G4DynamicParticle at rest
G4ThreeVector dummy;
auto parentparticle
= new G4DynamicParticle( G4MT_parent, dummy, 0.0);
auto parentparticle = new G4DynamicParticle(G4MT_parent, dummy, 0.0);
// create G4Decayproducts
auto products = new G4DecayProducts(*parentparticle);
delete parentparticle;
// calculate electron energy
G4double michel_rho = 0.75; //Standard Model Michel rho
G4double michel_delta = 0.75; //Standard Model Michel delta
G4double michel_xsi = 1.00; //Standard Model Michel xsi
G4double michel_eta = 0.00; //Standard Model eta
G4double michel_rho = 0.75; // Standard Model Michel rho
G4double michel_delta = 0.75; // Standard Model Michel delta
G4double michel_xsi = 1.00; // Standard Model Michel xsi
G4double michel_eta = 0.00; // Standard Model eta
G4double rndm, x, ctheta;
G4double FG;
G4double FG;
G4double FG_max = 2.00;
G4double W_mue = (EMMU*EMMU+EMASS*EMASS)/(2.*EMMU);
G4double x0 = EMASS/W_mue;
G4double W_mue = (EMMU * EMMU + EMASS * EMASS) / (2. * EMMU);
G4double x0 = EMASS / W_mue;
G4double x0_squared = x0 * x0;
G4double x0_squared = x0*x0;
// ***************************************************
// x0 <= x <= 1. and -1 <= y <= 1
//
@@ -143,64 +135,60 @@ G4DecayProducts* G4MuonDecayChannelWithSpin::DecayIt(G4double)
// ***** sampling F(x,y) directly (brute force) *****
const std::size_t MAX_LOOP=10000;
for (std::size_t loop_count=0; loop_count<MAX_LOOP; ++loop_count)
{
const std::size_t MAX_LOOP = 10000;
for (std::size_t loop_count = 0; loop_count < MAX_LOOP; ++loop_count) {
// Sample the positron energy by sampling from F
rndm = G4UniformRand();
x = x0 + rndm*(1.-x0);
x = x0 + rndm * (1. - x0);
G4double x_squared = x*x;
G4double x_squared = x * x;
G4double F_IS, F_AS, G_IS, G_AS;
F_IS = 1./6.*(-2.*x_squared+3.*x-x0_squared);
F_AS = 1./6.*std::sqrt(x_squared-x0_squared)
*(2.*x-2.+std::sqrt(1.-x0_squared));
F_IS = 1. / 6. * (-2. * x_squared + 3. * x - x0_squared);
F_AS = 1. / 6. * std::sqrt(x_squared - x0_squared) * (2. * x - 2. + std::sqrt(1. - x0_squared));
G_IS = 2./9.*(michel_rho-0.75)*(4.*x_squared-3.*x-x0_squared);
G_IS = G_IS + michel_eta*(1.-x)*x0;
G_IS = 2. / 9. * (michel_rho - 0.75) * (4. * x_squared - 3. * x - x0_squared);
G_IS = G_IS + michel_eta * (1. - x) * x0;
G_AS = 3.*(michel_xsi-1.)*(1.-x);
G_AS = G_AS+2.*(michel_xsi*michel_delta-0.75)
*(4.*x-4.+std::sqrt(1.-x0_squared));
G_AS = 1./9.*std::sqrt(x_squared-x0_squared)*G_AS;
G_AS = 3. * (michel_xsi - 1.) * (1. - x);
G_AS =
G_AS + 2. * (michel_xsi * michel_delta - 0.75) * (4. * x - 4. + std::sqrt(1. - x0_squared));
G_AS = 1. / 9. * std::sqrt(x_squared - x0_squared) * G_AS;
F_IS = F_IS + G_IS;
F_AS = F_AS + G_AS;
// *** Radiative Corrections ***
const G4double omega = std::log(EMMU/EMASS);
G4double R_IS = F_c(x,x0,omega);
const G4double omega = std::log(EMMU / EMASS);
G4double R_IS = F_c(x, x0, omega);
G4double F = 6.*F_IS + R_IS/std::sqrt(x_squared-x0_squared);
G4double F = 6. * F_IS + R_IS / std::sqrt(x_squared - x0_squared);
// *** Radiative Corrections ***
G4double R_AS = F_theta(x,x0,omega);
G4double R_AS = F_theta(x, x0, omega);
rndm = G4UniformRand();
ctheta = 2.*rndm-1.;
ctheta = 2. * rndm - 1.;
G4double G = 6.*F_AS - R_AS/std::sqrt(x_squared-x0_squared);
G4double G = 6. * F_AS - R_AS / std::sqrt(x_squared - x0_squared);
FG = std::sqrt(x_squared-x0_squared)*F*(1.+(G/F)*ctheta);
FG = std::sqrt(x_squared - x0_squared) * F * (1. + (G / F) * ctheta);
if(FG>FG_max)
{
G4Exception("G4MuonDecayChannelWithSpin::DecayIt()",
"PART113", JustWarning,
if (FG > FG_max) {
G4Exception("G4MuonDecayChannelWithSpin::DecayIt()", "PART113", JustWarning,
"Problem in Muon Decay: FG > FG_max");
FG_max = FG;
}
rndm = G4UniformRand();
if (FG >= rndm*FG_max) break;
if (FG >= rndm * FG_max) break;
}
G4double energy = x * W_mue;
@@ -209,57 +197,54 @@ G4DecayProducts* G4MuonDecayChannelWithSpin::DecayIt(G4double)
G4double phi = twopi * rndm;
if(energy < EMASS) energy = EMASS;
if (energy < EMASS) energy = EMASS;
// Calculate daughter momentum
G4double daughtermomentum[3];
daughtermomentum[0] = std::sqrt(energy*energy - EMASS*EMASS);
daughtermomentum[0] = std::sqrt(energy * energy - EMASS * EMASS);
G4double stheta = std::sqrt(1.-ctheta*ctheta);
G4double stheta = std::sqrt(1. - ctheta * ctheta);
G4double cphi = std::cos(phi);
G4double sphi = std::sin(phi);
// Coordinates of the decay positron with respect to the muon spin
G4double px = stheta*cphi;
G4double py = stheta*sphi;
G4double px = stheta * cphi;
G4double py = stheta * sphi;
G4double pz = ctheta;
G4ThreeVector direction0(px,py,pz);
G4ThreeVector direction0(px, py, pz);
direction0.rotateUz(parent_polarization);
auto daughterparticle0
= new G4DynamicParticle( G4MT_daughters[0], daughtermomentum[0]*direction0);
auto daughterparticle0 =
new G4DynamicParticle(G4MT_daughters[0], daughtermomentum[0] * direction0);
products->PushProducts(daughterparticle0);
// daughter 1 ,2 (neutrinos)
// create neutrinos in the C.M frame of two neutrinos
G4double energy2 = parentmass-energy;
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 energy2 = parentmass - energy;
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);
auto daughterparticle1
= new G4DynamicParticle( G4MT_daughters[1], direction1*(vmass/2.));
auto daughterparticle2
= new G4DynamicParticle( G4MT_daughters[2], direction1*(-1.0*vmass/2.));
G4ThreeVector direction1(sinthetan * cosphin, sinthetan * sinphin, costhetan);
auto daughterparticle1 = new G4DynamicParticle(G4MT_daughters[1], direction1 * (vmass / 2.));
auto daughterparticle2 =
new G4DynamicParticle(G4MT_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);
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);
p4.boost(direction0.x() * beta, direction0.y() * beta, direction0.z() * beta);
daughterparticle2->Set4Momentum(p4);
products->PushProducts(daughterparticle1);
products->PushProducts(daughterparticle2);
@@ -268,43 +253,42 @@ G4DecayProducts* G4MuonDecayChannelWithSpin::DecayIt(G4double)
// output message
#ifdef G4VERBOSE
if (GetVerboseLevel()>1)
{
if (GetVerboseLevel() > 1) {
G4cout << "G4MuonDecayChannelWithSpin::DecayIt ";
G4cout << " create decay products in rest frame " <<G4endl;
G4double TT = daughterparticle0->GetTotalEnergy()
+ daughterparticle1->GetTotalEnergy()
+ daughterparticle2->GetTotalEnergy();
G4cout << "e " << daughterparticle0->GetTotalEnergy()/MeV << G4endl;
G4cout << "nu1" << daughterparticle1->GetTotalEnergy()/MeV << G4endl;
G4cout << "nu2" << daughterparticle2->GetTotalEnergy()/MeV << G4endl;
G4cout << "total" << (TT-parentmass)/keV << G4endl;
if (GetVerboseLevel()>2) { products->DumpInfo(); }
G4cout << " create decay products in rest frame " << G4endl;
G4double TT = daughterparticle0->GetTotalEnergy() + daughterparticle1->GetTotalEnergy()
+ daughterparticle2->GetTotalEnergy();
G4cout << "e " << daughterparticle0->GetTotalEnergy() / MeV << G4endl;
G4cout << "nu1" << daughterparticle1->GetTotalEnergy() / MeV << G4endl;
G4cout << "nu2" << daughterparticle2->GetTotalEnergy() / MeV << G4endl;
G4cout << "total" << (TT - parentmass) / keV << G4endl;
if (GetVerboseLevel() > 2) {
products->DumpInfo();
}
}
#endif
return products;
}
G4double G4MuonDecayChannelWithSpin::R_c(G4double x,G4double omega)
G4double G4MuonDecayChannelWithSpin::R_c(G4double x, G4double omega)
{
auto n_max = (G4int)(100.*x);
auto n_max = (G4int)(100. * x);
if(n_max<10)n_max=10;
if (n_max < 10) n_max = 10;
G4double L2 = 0.0;
for(G4int n=1; n<=n_max; ++n)
{
L2 += std::pow(x,n)/(n*n);
for (G4int n = 1; n <= n_max; ++n) {
L2 += std::pow(x, n) / (n * n);
}
G4double r_c;
r_c = 2.*L2-(pi*pi/3.)-2.;
r_c = r_c + omega * (1.5+2.*std::log((1.-x)/x));
r_c = r_c - std::log(x)*(2.*std::log(x)-1.);
r_c = r_c + (3.*std::log(x)-1.-1./x)*std::log(1.-x);
r_c = 2. * L2 - (pi * pi / 3.) - 2.;
r_c = r_c + omega * (1.5 + 2. * std::log((1. - x) / x));
r_c = r_c - std::log(x) * (2. * std::log(x) - 1.);
r_c = r_c + (3. * std::log(x) - 1. - 1. / x) * std::log(1. - x);
return r_c;
}