1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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4 | // * * |
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5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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7 | // * conditions of the Geant4 Software License, included in the file * |
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8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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9 | // * include a list of copyright holders. * |
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10 | // * * |
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11 | // * Neither the authors of this software system, nor their employing * |
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12 | // * institutes,nor the agencies providing financial support for this * |
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13 | // * work make any representation or warranty, express or implied, * |
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14 | // * regarding this software system or assume any liability for its * |
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15 | // * use. Please see the license in the file LICENSE and URL above * |
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16 | // * for the full disclaimer and the limitation of liability. * |
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17 | // * * |
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18 | // * This code implementation is the result of the scientific and * |
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19 | // * technical work of the GEANT4 collaboration. * |
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20 | // * By using, copying, modifying or distributing the software (or * |
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21 | // * any work based on the software) you agree to acknowledge its * |
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22 | // * use in resulting scientific publications, and indicate your * |
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23 | // * acceptance of all terms of the Geant4 Software license. * |
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24 | // ******************************************************************** |
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25 | // |
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26 | // |
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27 | // $Id: G4KL3DecayChannel.cc,v 1.9 2009/08/17 14:52:19 kurasige Exp $ |
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28 | // GEANT4 tag $Name: geant4-09-03-cand-01 $ |
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29 | // |
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30 | // |
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31 | // ------------------------------------------------------------ |
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32 | // GEANT 4 class header file |
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33 | // |
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34 | // History: first implementation, based on object model of |
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35 | // 30 May 1997 H.Kurashige |
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36 | // ------------------------------------------------------------ |
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37 | |
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38 | #include "G4ParticleDefinition.hh" |
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39 | #include "G4DecayProducts.hh" |
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40 | #include "G4VDecayChannel.hh" |
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41 | #include "G4KL3DecayChannel.hh" |
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42 | #include "Randomize.hh" |
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43 | #include "G4LorentzVector.hh" |
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44 | #include "G4LorentzRotation.hh" |
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45 | |
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46 | |
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47 | G4KL3DecayChannel::G4KL3DecayChannel( |
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48 | const G4String& theParentName, |
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49 | G4double theBR, |
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50 | const G4String& thePionName, |
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51 | const G4String& theLeptonName, |
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52 | const G4String& theNutrinoName) |
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53 | :G4VDecayChannel("KL3 Decay",theParentName, |
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54 | theBR, 3, |
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55 | thePionName,theLeptonName,theNutrinoName) |
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56 | { |
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57 | static const G4String K_plus("kaon+"); |
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58 | static const G4String K_minus("kaon-"); |
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59 | static const G4String K_L("kaon0L"); |
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60 | static const G4String Mu_plus("mu+"); |
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61 | static const G4String Mu_minus("mu-"); |
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62 | static const G4String E_plus("e+"); |
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63 | static const G4String E_minus("e-"); |
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64 | |
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65 | // check modes |
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66 | if ( ((theParentName == K_plus)&&(theLeptonName == E_plus)) || |
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67 | ((theParentName == K_minus)&&(theLeptonName == E_minus)) ) { |
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68 | // K+- (Ke3) |
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69 | pLambda = 0.0286; |
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70 | pXi0 = -0.35; |
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71 | } else if ( ((theParentName == K_plus)&&(theLeptonName == Mu_plus)) || |
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72 | ((theParentName == K_minus)&&(theLeptonName == Mu_minus)) ) { |
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73 | // K+- (Kmu3) |
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74 | pLambda = 0.033; |
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75 | pXi0 = -0.35; |
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76 | } else if ( (theParentName == K_L) && |
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77 | ((theLeptonName == E_plus) ||(theLeptonName == E_minus)) ){ |
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78 | // K0L (Ke3) |
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79 | pLambda = 0.0300; |
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80 | pXi0 = -0.11; |
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81 | } else if ( (theParentName == K_L) && |
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82 | ((theLeptonName == Mu_plus) ||(theLeptonName == Mu_minus)) ){ |
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83 | // K0L (Kmu3) |
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84 | pLambda = 0.034; |
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85 | pXi0 = -0.11; |
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86 | } else { |
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87 | #ifdef G4VERBOSE |
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88 | if (GetVerboseLevel()>2) { |
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89 | G4cout << "G4KL3DecayChannel:: constructor :"; |
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90 | G4cout << "illegal arguments " << G4endl;; |
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91 | DumpInfo(); |
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92 | } |
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93 | #endif |
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94 | // set values for K0L (Ke3) temporarily |
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95 | pLambda = 0.0300; |
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96 | pXi0 = -0.11; |
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97 | } |
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98 | } |
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99 | |
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100 | G4KL3DecayChannel::~G4KL3DecayChannel() |
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101 | { |
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102 | } |
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103 | |
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104 | G4DecayProducts* G4KL3DecayChannel::DecayIt(G4double) |
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105 | { |
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106 | // this version neglects muon polarization |
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107 | // assumes the pure V-A coupling |
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108 | // gives incorrect energy spectrum for Nutrinos |
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109 | #ifdef G4VERBOSE |
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110 | if (GetVerboseLevel()>1) G4cout << "G4KL3DecayChannel::DecayIt " << G4endl; |
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111 | #endif |
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112 | |
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113 | // fill parent particle and its mass |
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114 | if (parent == 0) { |
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115 | FillParent(); |
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116 | } |
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117 | massK = parent->GetPDGMass(); |
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118 | |
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119 | // fill daughter particles and their mass |
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120 | if (daughters == 0) { |
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121 | FillDaughters(); |
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122 | } |
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123 | daughterM[idPi] = daughters[idPi]->GetPDGMass(); |
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124 | daughterM[idLepton] = daughters[idLepton]->GetPDGMass(); |
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125 | daughterM[idNutrino] = daughters[idNutrino]->GetPDGMass(); |
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126 | |
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127 | // determine momentum/energy of daughters |
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128 | // according to DalitzDensity |
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129 | G4double daughterP[3], daughterE[3]; |
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130 | G4double w; |
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131 | G4double r; |
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132 | do { |
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133 | r = G4UniformRand(); |
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134 | PhaseSpace(massK, &daughterM[0], &daughterE[0], &daughterP[0]); |
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135 | w = DalitzDensity(daughterE[idPi],daughterE[idLepton],daughterE[idNutrino]); |
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136 | } while ( r > w); |
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137 | |
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138 | // output message |
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139 | #ifdef G4VERBOSE |
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140 | if (GetVerboseLevel()>1) { |
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141 | G4cout << *daughters_name[0] << ":" << daughterP[0]/GeV << "[GeV/c]" <<G4endl; |
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142 | G4cout << *daughters_name[1] << ":" << daughterP[1]/GeV << "[GeV/c]" <<G4endl; |
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143 | G4cout << *daughters_name[2] << ":" << daughterP[2]/GeV << "[GeV/c]" <<G4endl; |
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144 | } |
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145 | #endif |
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146 | //create parent G4DynamicParticle at rest |
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147 | G4ThreeVector* direction = new G4ThreeVector(1.0,0.0,0.0); |
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148 | G4DynamicParticle * parentparticle = new G4DynamicParticle( parent, *direction, 0.0); |
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149 | delete direction; |
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150 | |
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151 | //create G4Decayproducts |
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152 | G4DecayProducts *products = new G4DecayProducts(*parentparticle); |
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153 | delete parentparticle; |
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154 | |
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155 | //create daughter G4DynamicParticle |
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156 | G4double costheta, sintheta, phi, sinphi, cosphi; |
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157 | G4double costhetan, sinthetan, phin, sinphin, cosphin; |
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158 | |
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159 | // pion |
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160 | costheta = 2.*G4UniformRand()-1.0; |
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161 | sintheta = std::sqrt((1.0-costheta)*(1.0+costheta)); |
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162 | phi = twopi*G4UniformRand()*rad; |
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163 | sinphi = std::sin(phi); |
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164 | cosphi = std::cos(phi); |
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165 | direction = new G4ThreeVector(sintheta*cosphi,sintheta*sinphi,costheta); |
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166 | G4ThreeVector momentum0 = (*direction)*daughterP[0]; |
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167 | G4DynamicParticle * daughterparticle |
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168 | = new G4DynamicParticle( daughters[0], momentum0); |
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169 | products->PushProducts(daughterparticle); |
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170 | |
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171 | // neutrino |
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172 | costhetan = (daughterP[1]*daughterP[1]-daughterP[2]*daughterP[2]-daughterP[0]*daughterP[0])/(2.0*daughterP[2]*daughterP[0]); |
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173 | sinthetan = std::sqrt((1.0-costhetan)*(1.0+costhetan)); |
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174 | phin = twopi*G4UniformRand()*rad; |
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175 | sinphin = std::sin(phin); |
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176 | cosphin = std::cos(phin); |
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177 | direction->setX( sinthetan*cosphin*costheta*cosphi - sinthetan*sinphin*sinphi + costhetan*sintheta*cosphi); |
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178 | direction->setY( sinthetan*cosphin*costheta*sinphi + sinthetan*sinphin*cosphi + costhetan*sintheta*sinphi); |
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179 | direction->setZ( -sinthetan*cosphin*sintheta + costhetan*costheta); |
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180 | |
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181 | G4ThreeVector momentum2 = (*direction)*daughterP[2]; |
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182 | daughterparticle = new G4DynamicParticle( daughters[2], momentum2); |
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183 | products->PushProducts(daughterparticle); |
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184 | |
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185 | //lepton |
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186 | G4ThreeVector momentum1 = (momentum0 + momentum2) * (-1.0); |
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187 | daughterparticle = |
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188 | new G4DynamicParticle( daughters[1], momentum1); |
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189 | products->PushProducts(daughterparticle); |
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190 | |
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191 | #ifdef G4VERBOSE |
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192 | if (GetVerboseLevel()>1) { |
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193 | G4cout << "G4KL3DecayChannel::DecayIt "; |
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194 | G4cout << " create decay products in rest frame " <<G4endl; |
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195 | G4cout << " decay products address=" << products << G4endl; |
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196 | products->DumpInfo(); |
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197 | } |
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198 | #endif |
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199 | delete direction; |
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200 | return products; |
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201 | } |
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202 | |
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203 | void G4KL3DecayChannel::PhaseSpace(G4double parentM, |
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204 | const G4double* M, |
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205 | G4double* E, |
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206 | G4double* P ) |
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207 | // algorism of this code is originally written in GDECA3 of GEANT3 |
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208 | { |
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209 | |
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210 | //sum of daughters'mass |
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211 | G4double sumofdaughtermass = 0.0; |
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212 | G4int index; |
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213 | for (index=0; index<3; index++){ |
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214 | sumofdaughtermass += M[index]; |
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215 | } |
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216 | |
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217 | //calculate daughter momentum |
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218 | // Generate two |
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219 | G4double rd1, rd2, rd; |
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220 | G4double momentummax=0.0, momentumsum = 0.0; |
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221 | G4double energy; |
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222 | |
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223 | do { |
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224 | rd1 = G4UniformRand(); |
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225 | rd2 = G4UniformRand(); |
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226 | if (rd2 > rd1) { |
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227 | rd = rd1; |
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228 | rd1 = rd2; |
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229 | rd2 = rd; |
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230 | } |
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231 | momentummax = 0.0; |
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232 | momentumsum = 0.0; |
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233 | // daughter 0 |
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234 | energy = rd2*(parentM - sumofdaughtermass); |
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235 | P[0] = std::sqrt(energy*energy + 2.0*energy*M[0]); |
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236 | E[0] = energy; |
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237 | if ( P[0] >momentummax )momentummax = P[0]; |
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238 | momentumsum += P[0]; |
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239 | // daughter 1 |
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240 | energy = (1.-rd1)*(parentM - sumofdaughtermass); |
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241 | P[1] = std::sqrt(energy*energy + 2.0*energy*M[1]); |
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242 | E[1] = energy; |
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243 | if ( P[1] >momentummax )momentummax = P[1]; |
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244 | momentumsum += P[1]; |
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245 | // daughter 2 |
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246 | energy = (rd1-rd2)*(parentM - sumofdaughtermass); |
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247 | P[2] = std::sqrt(energy*energy + 2.0*energy*M[2]); |
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248 | E[2] = energy; |
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249 | if ( P[2] >momentummax )momentummax = P[2]; |
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250 | momentumsum += P[2]; |
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251 | } while (momentummax > momentumsum - momentummax ); |
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252 | |
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253 | #ifdef G4VERBOSE |
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254 | if (GetVerboseLevel()>2) { |
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255 | G4cout << "G4KL3DecayChannel::PhaseSpace "; |
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256 | G4cout << "Kon mass:" << parentM/GeV << "GeV/c/c" << G4endl; |
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257 | for (index=0; index<3; index++){ |
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258 | G4cout << index << " : " << M[index]/GeV << "GeV/c/c "; |
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259 | G4cout << " : " << E[index]/GeV << "GeV "; |
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260 | G4cout << " : " << P[index]/GeV << "GeV/c " << G4endl; |
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261 | } |
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262 | } |
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263 | #endif |
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264 | } |
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265 | |
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266 | |
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267 | G4double G4KL3DecayChannel::DalitzDensity(G4double Epi, G4double El, G4double Enu) |
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268 | { |
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269 | // KL3 decay Dalitz Plot Density |
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270 | // see Chounet et al Phys. Rep. 4, 201 |
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271 | // arguments |
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272 | // Epi: kinetic enregy of pion |
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273 | // El: kinetic enregy of lepton (e or mu) |
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274 | // Enu: kinetic energy of nutrino |
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275 | // constants |
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276 | // pLambda : linear energy dependence of f+ |
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277 | // pXi0 : = f+(0)/f- |
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278 | // pNorm : normalization factor |
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279 | // variables |
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280 | // Epi: total energy of pion |
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281 | // El: total energy of lepton (e or mu) |
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282 | // Enu: total energy of nutrino |
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283 | |
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284 | // mass of daughters |
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285 | G4double massPi = daughterM[idPi]; |
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286 | G4double massL = daughterM[idLepton]; |
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287 | G4double massNu = daughterM[idNutrino]; |
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288 | |
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289 | // calcurate total energy |
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290 | Epi = Epi + massPi; |
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291 | El = El + massL; |
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292 | Enu = Enu + massNu; |
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293 | |
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294 | G4double Epi_max = (massK*massK+massPi*massPi-massL*massL)/2.0/massK; |
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295 | G4double E = Epi_max - Epi; |
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296 | G4double q2 = massK*massK + massPi*massPi - 2.0*massK*Epi; |
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297 | |
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298 | G4double F = 1.0 + pLambda*q2/massPi/massPi; |
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299 | G4double Fmax = 1.0; |
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300 | if (pLambda >0.0) Fmax = (1.0 + pLambda*(massK*massK/massPi/massPi+1.0)); |
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301 | |
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302 | G4double Xi = pXi0*(1.0 + pLambda*q2/massPi/massPi); |
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303 | |
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304 | G4double coeffA = massK*(2.0*El*Enu-massK*E)+massL*massL*(E/4.0-Enu); |
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305 | G4double coeffB = massL*massL*(Enu-E/2.0); |
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306 | G4double coeffC = massL*massL*E/4.0; |
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307 | |
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308 | G4double RhoMax = (Fmax*Fmax)*(massK*massK*massK/8.0); |
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309 | |
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310 | G4double Rho = (F*F)*(coeffA + coeffB*Xi + coeffC*Xi*Xi); |
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311 | |
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312 | #ifdef G4VERBOSE |
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313 | if (GetVerboseLevel()>2) { |
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314 | G4cout << "G4KL3DecayChannel::DalitzDensity " <<G4endl; |
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315 | G4cout << " Pi[" << massPi/GeV <<"GeV/c/c] :" << Epi/GeV << "GeV" <<G4endl; |
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316 | G4cout << " L[" << massL/GeV <<"GeV/c/c] :" << El/GeV << "GeV" <<G4endl; |
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317 | G4cout << " Nu[" << massNu/GeV <<"GeV/c/c] :" << Enu/GeV << "GeV" <<G4endl; |
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318 | G4cout << " F :" << F << " Fmax :" << Fmax << " Xi :" << Xi << G4endl; |
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319 | G4cout << " A :" << coeffA << " B :" << coeffB << " C :"<< coeffC <<G4endl; |
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320 | G4cout << " Rho :" << Rho << " RhoMax :" << RhoMax << G4endl; |
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321 | } |
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322 | #endif |
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323 | return (Rho/RhoMax); |
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324 | } |
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325 | |
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326 | |
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