[824] | 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 1.8 2006/06/29 19:25:32 gunter Exp $ |
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| 28 | // GEANT4 tag $Name: $ |
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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 | //#ifdef G4VERBOSE |
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| 58 | //if (GetVerboseLevel()>1) { |
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| 59 | // G4cout << "G4KL3DecayChannel:: constructor "; |
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| 60 | // G4cout << "addr[" << this << "]" << G4endl; |
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| 61 | //} |
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| 62 | //#endif |
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| 63 | // check modes |
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| 64 | if ( ((theParentName == "kaon+")&&(theLeptonName == "e+")) || |
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| 65 | ((theParentName == "kaon-")&&(theLeptonName == "e-")) ) { |
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| 66 | // K+- (Ke3) |
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| 67 | pLambda = 0.0286; |
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| 68 | pXi0 = -0.35; |
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| 69 | } else if ( ((theParentName == "kaon+")&&(theLeptonName == "mu+")) || |
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| 70 | ((theParentName == "kaon-")&&(theLeptonName == "mu-")) ) { |
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| 71 | // K+- (Kmu3) |
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| 72 | pLambda = 0.033; |
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| 73 | pXi0 = -0.35; |
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| 74 | } else if ( (theParentName == "kaon0L") && |
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| 75 | ((theLeptonName == "e+") ||(theLeptonName == "e-")) ){ |
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| 76 | // K0L (Ke3) |
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| 77 | pLambda = 0.0300; |
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| 78 | pXi0 = -0.11; |
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| 79 | } else if ( (theParentName == "kaon0L") && |
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| 80 | ((theLeptonName == "mu+") ||(theLeptonName == "mu-")) ){ |
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| 81 | // K0L (Kmu3) |
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| 82 | pLambda = 0.034; |
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| 83 | pXi0 = -0.11; |
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| 84 | } else { |
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| 85 | //#ifdef G4VERBOSE |
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| 86 | //if (GetVerboseLevel()>0) { |
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| 87 | // G4cout << "G4KL3DecayChannel:: constructor :"; |
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| 88 | // G4cout << "illegal arguments " << G4endl;; |
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| 89 | // DumpInfo(); |
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| 90 | // } |
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| 91 | //#endif |
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| 92 | // set values for K0L (Ke3) temporarily |
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| 93 | pLambda = 0.0300; |
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| 94 | pXi0 = -0.11; |
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| 95 | } |
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| 96 | } |
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| 97 | |
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| 98 | G4KL3DecayChannel::~G4KL3DecayChannel() |
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| 99 | { |
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| 100 | } |
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| 101 | |
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| 102 | G4DecayProducts* G4KL3DecayChannel::DecayIt(G4double) |
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| 103 | { |
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| 104 | // this version neglects muon polarization |
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| 105 | // assumes the pure V-A coupling |
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| 106 | // gives incorrect energy spectrum for Nutrinos |
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| 107 | #ifdef G4VERBOSE |
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| 108 | if (GetVerboseLevel()>1) G4cout << "G4KL3DecayChannel::DecayIt " << G4endl; |
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| 109 | #endif |
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| 110 | // fill parent particle and its mass |
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| 111 | if (parent == 0) { |
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| 112 | FillParent(); |
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| 113 | } |
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| 114 | massK = parent->GetPDGMass(); |
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| 115 | |
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| 116 | // fill daughter particles and their mass |
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| 117 | if (daughters == 0) { |
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| 118 | FillDaughters(); |
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| 119 | } |
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| 120 | daughterM[idPi] = daughters[idPi]->GetPDGMass(); |
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| 121 | daughterM[idLepton] = daughters[idLepton]->GetPDGMass(); |
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| 122 | daughterM[idNutrino] = daughters[idNutrino]->GetPDGMass(); |
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| 123 | |
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| 124 | // determine momentum/energy of daughters |
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| 125 | // according to DalitzDensity |
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| 126 | G4double daughterP[3], daughterE[3]; |
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| 127 | G4double w; |
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| 128 | G4double r; |
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| 129 | do { |
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| 130 | r = G4UniformRand(); |
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| 131 | PhaseSpace(massK, &daughterM[0], &daughterE[0], &daughterP[0]); |
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| 132 | w = DalitzDensity(daughterE[idPi],daughterE[idLepton],daughterE[idNutrino]); |
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| 133 | } while ( r > w); |
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| 134 | |
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| 135 | // output message |
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| 136 | #ifdef G4VERBOSE |
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| 137 | if (GetVerboseLevel()>1) { |
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| 138 | G4cout << *daughters_name[0] << ":" << daughterP[0]/GeV << "[GeV/c]" <<G4endl; |
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| 139 | G4cout << *daughters_name[1] << ":" << daughterP[1]/GeV << "[GeV/c]" <<G4endl; |
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| 140 | G4cout << *daughters_name[2] << ":" << daughterP[2]/GeV << "[GeV/c]" <<G4endl; |
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| 141 | } |
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| 142 | #endif |
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| 143 | //create parent G4DynamicParticle at rest |
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| 144 | G4ThreeVector* direction = new G4ThreeVector(1.0,0.0,0.0); |
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| 145 | G4DynamicParticle * parentparticle = new G4DynamicParticle( parent, *direction, 0.0); |
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| 146 | delete direction; |
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| 147 | |
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| 148 | //create G4Decayproducts |
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| 149 | G4DecayProducts *products = new G4DecayProducts(*parentparticle); |
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| 150 | delete parentparticle; |
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| 151 | |
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| 152 | //create daughter G4DynamicParticle |
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| 153 | G4double costheta, sintheta, phi, sinphi, cosphi; |
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| 154 | G4double costhetan, sinthetan, phin, sinphin, cosphin; |
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| 155 | |
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| 156 | // pion |
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| 157 | costheta = 2.*G4UniformRand()-1.0; |
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| 158 | sintheta = std::sqrt((1.0-costheta)*(1.0+costheta)); |
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| 159 | phi = twopi*G4UniformRand()*rad; |
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| 160 | sinphi = std::sin(phi); |
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| 161 | cosphi = std::cos(phi); |
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| 162 | direction = new G4ThreeVector(sintheta*cosphi,sintheta*sinphi,costheta); |
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| 163 | G4ThreeVector momentum0 = (*direction)*daughterP[0]; |
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| 164 | G4DynamicParticle * daughterparticle |
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| 165 | = new G4DynamicParticle( daughters[0], momentum0); |
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| 166 | products->PushProducts(daughterparticle); |
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| 167 | |
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| 168 | // neutrino |
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| 169 | costhetan = (daughterP[1]*daughterP[1]-daughterP[2]*daughterP[2]-daughterP[0]*daughterP[0])/(2.0*daughterP[2]*daughterP[0]); |
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| 170 | sinthetan = std::sqrt((1.0-costhetan)*(1.0+costhetan)); |
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| 171 | phin = twopi*G4UniformRand()*rad; |
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| 172 | sinphin = std::sin(phin); |
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| 173 | cosphin = std::cos(phin); |
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| 174 | direction->setX( sinthetan*cosphin*costheta*cosphi - sinthetan*sinphin*sinphi + costhetan*sintheta*cosphi); |
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| 175 | direction->setY( sinthetan*cosphin*costheta*sinphi + sinthetan*sinphin*cosphi + costhetan*sintheta*sinphi); |
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| 176 | direction->setZ( -sinthetan*cosphin*sintheta + costhetan*costheta); |
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| 177 | |
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| 178 | G4ThreeVector momentum2 = (*direction)*daughterP[2]; |
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| 179 | daughterparticle = new G4DynamicParticle( daughters[2], momentum2); |
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| 180 | products->PushProducts(daughterparticle); |
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| 181 | |
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| 182 | //lepton |
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| 183 | G4ThreeVector momentum1 = (momentum0 + momentum2) * (-1.0); |
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| 184 | daughterparticle = |
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| 185 | new G4DynamicParticle( daughters[1], momentum1); |
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| 186 | products->PushProducts(daughterparticle); |
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| 187 | |
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| 188 | #ifdef G4VERBOSE |
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| 189 | if (GetVerboseLevel()>1) { |
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| 190 | G4cout << "G4KL3DecayChannel::DecayIt "; |
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| 191 | G4cout << " create decay products in rest frame " <<G4endl; |
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| 192 | G4cout << " decay products address=" << products << G4endl; |
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| 193 | products->DumpInfo(); |
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| 194 | } |
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| 195 | #endif |
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| 196 | delete direction; |
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| 197 | return products; |
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| 198 | } |
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| 199 | |
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| 200 | void G4KL3DecayChannel::PhaseSpace(G4double parentM, |
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| 201 | const G4double* M, |
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| 202 | G4double* E, |
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| 203 | G4double* P ) |
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| 204 | // algorism of this code is originally written in GDECA3 of GEANT3 |
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| 205 | { |
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| 206 | |
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| 207 | //sum of daughters'mass |
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| 208 | G4double sumofdaughtermass = 0.0; |
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| 209 | G4int index; |
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| 210 | for (index=0; index<3; index++){ |
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| 211 | sumofdaughtermass += M[index]; |
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| 212 | } |
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| 213 | |
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| 214 | //calculate daughter momentum |
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| 215 | // Generate two |
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| 216 | G4double rd1, rd2, rd; |
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| 217 | G4double momentummax=0.0, momentumsum = 0.0; |
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| 218 | G4double energy; |
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| 219 | |
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| 220 | do { |
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| 221 | rd1 = G4UniformRand(); |
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| 222 | rd2 = G4UniformRand(); |
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| 223 | if (rd2 > rd1) { |
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| 224 | rd = rd1; |
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| 225 | rd1 = rd2; |
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| 226 | rd2 = rd; |
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| 227 | } |
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| 228 | momentummax = 0.0; |
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| 229 | momentumsum = 0.0; |
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| 230 | // daughter 0 |
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| 231 | energy = rd2*(parentM - sumofdaughtermass); |
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| 232 | P[0] = std::sqrt(energy*energy + 2.0*energy*M[0]); |
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| 233 | E[0] = energy; |
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| 234 | if ( P[0] >momentummax )momentummax = P[0]; |
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| 235 | momentumsum += P[0]; |
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| 236 | // daughter 1 |
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| 237 | energy = (1.-rd1)*(parentM - sumofdaughtermass); |
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| 238 | P[1] = std::sqrt(energy*energy + 2.0*energy*M[1]); |
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| 239 | E[1] = energy; |
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| 240 | if ( P[1] >momentummax )momentummax = P[1]; |
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| 241 | momentumsum += P[1]; |
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| 242 | // daughter 2 |
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| 243 | energy = (rd1-rd2)*(parentM - sumofdaughtermass); |
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| 244 | P[2] = std::sqrt(energy*energy + 2.0*energy*M[2]); |
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| 245 | E[2] = energy; |
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| 246 | if ( P[2] >momentummax )momentummax = P[2]; |
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| 247 | momentumsum += P[2]; |
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| 248 | } while (momentummax > momentumsum - momentummax ); |
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| 249 | |
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| 250 | #ifdef G4VERBOSE |
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| 251 | if (GetVerboseLevel()>2) { |
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| 252 | G4cout << "G4KL3DecayChannel::PhaseSpace "; |
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| 253 | G4cout << "Kon mass:" << parentM/GeV << "GeV/c/c" << G4endl; |
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| 254 | for (index=0; index<3; index++){ |
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| 255 | G4cout << index << " : " << M[index]/GeV << "GeV/c/c "; |
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| 256 | G4cout << " : " << E[index]/GeV << "GeV "; |
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| 257 | G4cout << " : " << P[index]/GeV << "GeV/c " << G4endl; |
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| 258 | } |
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| 259 | } |
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| 260 | #endif |
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| 261 | } |
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| 262 | |
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| 263 | |
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| 264 | G4double G4KL3DecayChannel::DalitzDensity(G4double Epi, G4double El, G4double Enu) |
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| 265 | { |
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| 266 | // KL3 decay Dalitz Plot Density |
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| 267 | // see Chounet et al Phys. Rep. 4, 201 |
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| 268 | // arguments |
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| 269 | // Epi: kinetic enregy of pion |
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| 270 | // El: kinetic enregy of lepton (e or mu) |
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| 271 | // Enu: kinetic energy of nutrino |
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| 272 | // constants |
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| 273 | // pLambda : linear energy dependence of f+ |
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| 274 | // pXi0 : = f+(0)/f- |
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| 275 | // pNorm : normalization factor |
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| 276 | // variables |
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| 277 | // Epi: total energy of pion |
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| 278 | // El: total energy of lepton (e or mu) |
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| 279 | // Enu: total energy of nutrino |
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| 280 | |
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| 281 | // mass of daughters |
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| 282 | G4double massPi = daughterM[idPi]; |
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| 283 | G4double massL = daughterM[idLepton]; |
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| 284 | G4double massNu = daughterM[idNutrino]; |
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| 285 | |
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| 286 | // calcurate total energy |
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| 287 | Epi = Epi + massPi; |
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| 288 | El = El + massL; |
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| 289 | Enu = Enu + massNu; |
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| 290 | |
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| 291 | G4double Epi_max = (massK*massK+massPi*massPi-massL*massL)/2.0/massK; |
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| 292 | G4double E = Epi_max - Epi; |
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| 293 | G4double q2 = massK*massK + massPi*massPi - 2.0*massK*Epi; |
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| 294 | |
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| 295 | G4double F = 1.0 + pLambda*q2/massPi/massPi; |
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| 296 | G4double Fmax = 1.0; |
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| 297 | if (pLambda >0.0) Fmax = (1.0 + pLambda*(massK*massK/massPi/massPi+1.0)); |
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| 298 | |
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| 299 | G4double Xi = pXi0*(1.0 + pLambda*q2/massPi/massPi); |
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| 300 | |
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| 301 | G4double coeffA = massK*(2.0*El*Enu-massK*E)+massL*massL*(E/4.0-Enu); |
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| 302 | G4double coeffB = massL*massL*(Enu-E/2.0); |
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| 303 | G4double coeffC = massL*massL*E/4.0; |
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| 304 | |
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| 305 | G4double RhoMax = (Fmax*Fmax)*(massK*massK*massK/8.0); |
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| 306 | |
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| 307 | G4double Rho = (F*F)*(coeffA + coeffB*Xi + coeffC*Xi*Xi); |
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| 308 | |
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| 309 | #ifdef G4VERBOSE |
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| 310 | if (GetVerboseLevel()>2) { |
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| 311 | G4cout << "G4KL3DecayChannel::DalitzDensity " <<G4endl; |
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| 312 | G4cout << " Pi[" << massPi/GeV <<"GeV/c/c] :" << Epi/GeV << "GeV" <<G4endl; |
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| 313 | G4cout << " L[" << massL/GeV <<"GeV/c/c] :" << El/GeV << "GeV" <<G4endl; |
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| 314 | G4cout << " Nu[" << massNu/GeV <<"GeV/c/c] :" << Enu/GeV << "GeV" <<G4endl; |
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| 315 | G4cout << " F :" << F << " Fmax :" << Fmax << " Xi :" << Xi << G4endl; |
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| 316 | G4cout << " A :" << coeffA << " B :" << coeffB << " C :"<< coeffC <<G4endl; |
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| 317 | G4cout << " Rho :" << Rho << " RhoMax :" << RhoMax << G4endl; |
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| 318 | } |
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| 319 | #endif |
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| 320 | return (Rho/RhoMax); |
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| 321 | } |
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| 322 | |
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| 323 | |
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