[824] | 1 | // |
---|
| 2 | // ******************************************************************** |
---|
| 3 | // * License and Disclaimer * |
---|
| 4 | // * * |
---|
| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
---|
| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
---|
| 7 | // * conditions of the Geant4 Software License, included in the file * |
---|
| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
---|
| 9 | // * include a list of copyright holders. * |
---|
| 10 | // * * |
---|
| 11 | // * Neither the authors of this software system, nor their employing * |
---|
| 12 | // * institutes,nor the agencies providing financial support for this * |
---|
| 13 | // * work make any representation or warranty, express or implied, * |
---|
| 14 | // * regarding this software system or assume any liability for its * |
---|
| 15 | // * use. Please see the license in the file LICENSE and URL above * |
---|
| 16 | // * for the full disclaimer and the limitation of liability. * |
---|
| 17 | // * * |
---|
| 18 | // * This code implementation is the result of the scientific and * |
---|
| 19 | // * technical work of the GEANT4 collaboration. * |
---|
| 20 | // * By using, copying, modifying or distributing the software (or * |
---|
| 21 | // * any work based on the software) you agree to acknowledge its * |
---|
| 22 | // * use in resulting scientific publications, and indicate your * |
---|
| 23 | // * acceptance of all terms of the Geant4 Software license. * |
---|
| 24 | // ******************************************************************** |
---|
| 25 | // |
---|
| 26 | // |
---|
| 27 | // $Id: G4MuonDecayChannel.cc,v 1.17 2006/06/29 19:25:34 gunter Exp $ |
---|
[1196] | 28 | // GEANT4 tag $Name: geant4-09-03-cand-01 $ |
---|
[824] | 29 | // |
---|
| 30 | // |
---|
| 31 | // ------------------------------------------------------------ |
---|
| 32 | // GEANT 4 class header file |
---|
| 33 | // |
---|
| 34 | // History: first implementation, based on object model of |
---|
| 35 | // 30 May 1997 H.Kurashige |
---|
| 36 | // |
---|
| 37 | // Fix bug in calcuration of electron energy in DecayIt 28 Feb. 01 H.Kurashige |
---|
| 38 | //2005 |
---|
| 39 | // M. Melissas ( melissas AT cppm.in2p3.fr) |
---|
| 40 | // J. Brunner ( brunner AT cppm.in2p3.fr) |
---|
| 41 | // Adding V-A fluxes for neutrinos using a new algortithm : |
---|
| 42 | // ------------------------------------------------------------ |
---|
| 43 | |
---|
| 44 | #include "G4ParticleDefinition.hh" |
---|
| 45 | #include "G4DecayProducts.hh" |
---|
| 46 | #include "G4VDecayChannel.hh" |
---|
| 47 | #include "G4MuonDecayChannel.hh" |
---|
| 48 | #include "Randomize.hh" |
---|
| 49 | #include "G4LorentzVector.hh" |
---|
| 50 | #include "G4LorentzRotation.hh" |
---|
| 51 | #include "G4RotationMatrix.hh" |
---|
| 52 | |
---|
| 53 | |
---|
| 54 | G4MuonDecayChannel::G4MuonDecayChannel(const G4String& theParentName, |
---|
| 55 | G4double theBR) |
---|
| 56 | :G4VDecayChannel("Muon Decay",1) |
---|
| 57 | { |
---|
| 58 | // set names for daughter particles |
---|
| 59 | if (theParentName == "mu+") { |
---|
| 60 | SetBR(theBR); |
---|
| 61 | SetParent("mu+"); |
---|
| 62 | SetNumberOfDaughters(3); |
---|
| 63 | SetDaughter(0, "e+"); |
---|
| 64 | SetDaughter(1, "nu_e"); |
---|
| 65 | SetDaughter(2, "anti_nu_mu"); |
---|
| 66 | } else if (theParentName == "mu-") { |
---|
| 67 | SetBR(theBR); |
---|
| 68 | SetParent("mu-"); |
---|
| 69 | SetNumberOfDaughters(3); |
---|
| 70 | SetDaughter(0, "e-"); |
---|
| 71 | SetDaughter(1, "anti_nu_e"); |
---|
| 72 | SetDaughter(2, "nu_mu"); |
---|
| 73 | } else { |
---|
| 74 | #ifdef G4VERBOSE |
---|
| 75 | if (GetVerboseLevel()>0) { |
---|
| 76 | G4cout << "G4MuonDecayChannel:: constructor :"; |
---|
| 77 | G4cout << " parent particle is not muon but "; |
---|
| 78 | G4cout << theParentName << G4endl; |
---|
| 79 | } |
---|
| 80 | #endif |
---|
| 81 | } |
---|
| 82 | } |
---|
| 83 | |
---|
| 84 | G4MuonDecayChannel::~G4MuonDecayChannel() |
---|
| 85 | { |
---|
| 86 | } |
---|
| 87 | |
---|
| 88 | G4DecayProducts *G4MuonDecayChannel::DecayIt(G4double) |
---|
| 89 | { |
---|
| 90 | // this version neglects muon polarization,and electron mass |
---|
| 91 | // assumes the pure V-A coupling |
---|
| 92 | // the Neutrinos are correctly V-A. |
---|
| 93 | #ifdef G4VERBOSE |
---|
| 94 | if (GetVerboseLevel()>1) G4cout << "G4MuonDecayChannel::DecayIt "; |
---|
| 95 | #endif |
---|
| 96 | |
---|
| 97 | if (parent == 0) FillParent(); |
---|
| 98 | if (daughters == 0) FillDaughters(); |
---|
| 99 | |
---|
| 100 | // parent mass |
---|
| 101 | G4double parentmass = parent->GetPDGMass(); |
---|
| 102 | |
---|
| 103 | //daughters'mass |
---|
| 104 | G4double daughtermass[3]; |
---|
| 105 | G4double sumofdaughtermass = 0.0; |
---|
| 106 | for (G4int index=0; index<3; index++){ |
---|
| 107 | daughtermass[index] = daughters[index]->GetPDGMass(); |
---|
| 108 | sumofdaughtermass += daughtermass[index]; |
---|
| 109 | } |
---|
| 110 | |
---|
| 111 | //create parent G4DynamicParticle at rest |
---|
| 112 | G4ThreeVector dummy; |
---|
| 113 | G4DynamicParticle * parentparticle = new G4DynamicParticle( parent, dummy, 0.0); |
---|
| 114 | //create G4Decayproducts |
---|
| 115 | G4DecayProducts *products = new G4DecayProducts(*parentparticle); |
---|
| 116 | delete parentparticle; |
---|
| 117 | |
---|
| 118 | // calculate daughter momentum |
---|
| 119 | G4double daughtermomentum[3]; |
---|
| 120 | // calcurate electron energy |
---|
| 121 | G4double xmax = (1.0+daughtermass[0]*daughtermass[0]/parentmass/parentmass); |
---|
| 122 | G4double x; |
---|
| 123 | |
---|
| 124 | G4double Ee,Ene; |
---|
| 125 | |
---|
| 126 | G4double gam; |
---|
| 127 | G4double EMax=parentmass/2-daughtermass[0]; |
---|
| 128 | |
---|
| 129 | |
---|
| 130 | //Generating Random Energy |
---|
| 131 | do { |
---|
| 132 | Ee=G4UniformRand(); |
---|
| 133 | do{ |
---|
| 134 | x=xmax*G4UniformRand(); |
---|
| 135 | gam=G4UniformRand(); |
---|
| 136 | }while (gam >x*(1.-x)); |
---|
| 137 | Ene=x; |
---|
| 138 | } while ( Ene < (1.-Ee)); |
---|
| 139 | G4double Enm=(2.-Ee-Ene); |
---|
| 140 | |
---|
| 141 | |
---|
| 142 | //initialisation of rotation parameters |
---|
| 143 | |
---|
| 144 | G4double costheta,sintheta,rphi,rtheta,rpsi; |
---|
| 145 | costheta= 1.-2./Ee-2./Ene+2./Ene/Ee; |
---|
| 146 | sintheta=std::sqrt(1.-costheta*costheta); |
---|
| 147 | |
---|
| 148 | |
---|
| 149 | rphi=twopi*G4UniformRand()*rad; |
---|
| 150 | rtheta=(std::acos(2.*G4UniformRand()-1.)); |
---|
| 151 | rpsi=twopi*G4UniformRand()*rad; |
---|
| 152 | |
---|
| 153 | G4RotationMatrix rot; |
---|
| 154 | rot.set(rphi,rtheta,rpsi); |
---|
| 155 | |
---|
| 156 | //electron 0 |
---|
| 157 | daughtermomentum[0]=std::sqrt(Ee*Ee*EMax*EMax+2.0*Ee*EMax * daughtermass[0]); |
---|
| 158 | G4ThreeVector direction0(0.0,0.0,1.0); |
---|
| 159 | |
---|
| 160 | direction0 *= rot; |
---|
| 161 | |
---|
| 162 | G4DynamicParticle * daughterparticle = new G4DynamicParticle ( daughters[0], direction0 * daughtermomentum[0]); |
---|
| 163 | |
---|
| 164 | products->PushProducts(daughterparticle); |
---|
| 165 | |
---|
| 166 | //electronic neutrino 1 |
---|
| 167 | |
---|
| 168 | daughtermomentum[1]=std::sqrt(Ene*Ene*EMax*EMax+2.0*Ene*EMax * daughtermass[1]); |
---|
| 169 | G4ThreeVector direction1(sintheta,0.0,costheta); |
---|
| 170 | |
---|
| 171 | direction1 *= rot; |
---|
| 172 | |
---|
| 173 | G4DynamicParticle * daughterparticle1 = new G4DynamicParticle ( daughters[1], direction1 * daughtermomentum[1]); |
---|
| 174 | products->PushProducts(daughterparticle1); |
---|
| 175 | |
---|
| 176 | //muonnic neutrino 2 |
---|
| 177 | |
---|
| 178 | daughtermomentum[2]=std::sqrt(Enm*Enm*EMax*EMax +2.0*Enm*EMax*daughtermass[2]); |
---|
| 179 | G4ThreeVector direction2(-Ene/Enm*sintheta,0,-Ee/Enm-Ene/Enm*costheta); |
---|
| 180 | |
---|
| 181 | direction2 *= rot; |
---|
| 182 | |
---|
| 183 | G4DynamicParticle * daughterparticle2 = new G4DynamicParticle ( daughters[2], |
---|
| 184 | direction2 * daughtermomentum[2]); |
---|
| 185 | products->PushProducts(daughterparticle2); |
---|
| 186 | |
---|
| 187 | |
---|
| 188 | |
---|
| 189 | |
---|
| 190 | // output message |
---|
| 191 | #ifdef G4VERBOSE |
---|
| 192 | if (GetVerboseLevel()>1) { |
---|
| 193 | G4cout << "G4MuonDecayChannel::DecayIt "; |
---|
| 194 | G4cout << " create decay products in rest frame " <<G4endl; |
---|
| 195 | products->DumpInfo(); |
---|
| 196 | } |
---|
| 197 | #endif |
---|
| 198 | return products; |
---|
| 199 | } |
---|
| 200 | |
---|
| 201 | |
---|
| 202 | |
---|
| 203 | |
---|
| 204 | |
---|
| 205 | |
---|