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Please see the license in the file LICENSE and URL above * 16 // * for the full disclaimer and the limitatio 16 // * for the full disclaimer and the limitation of liability. * 17 // * 17 // * * 18 // * This code implementation is the result 18 // * This code implementation is the result of the scientific and * 19 // * technical work of the GEANT4 collaboratio 19 // * technical work of the GEANT4 collaboration. * 20 // * By using, copying, modifying or distri 20 // * By using, copying, modifying or distributing the software (or * 21 // * any work based on the software) you ag 21 // * any work based on the software) you agree to acknowledge its * 22 // * use in resulting scientific publicati 22 // * use in resulting scientific publications, and indicate your * 23 // * acceptance of all terms of the Geant4 Sof 23 // * acceptance of all terms of the Geant4 Software license. * 24 // ******************************************* 24 // ******************************************************************** 25 // 25 // >> 26 // >> 27 // >> 28 // 26 // G4 Model: Charge and strangness exchange ba 29 // G4 Model: Charge and strangness exchange based on G4LightMedia model 27 // 28 May 2006 V.Ivanchenko 30 // 28 May 2006 V.Ivanchenko 28 // 31 // 29 // Modified: 32 // Modified: 30 // 07-Jun-06 V.Ivanchenko fix problem of rotat 33 // 07-Jun-06 V.Ivanchenko fix problem of rotation of final state 31 // 25-Jul-06 V.Ivanchenko add 19 MeV low energ 34 // 25-Jul-06 V.Ivanchenko add 19 MeV low energy, below which S-wave is sampled 32 // 12-Jun-12 A.Ribon fix warnings of shadowed 35 // 12-Jun-12 A.Ribon fix warnings of shadowed variables 33 // 06-Aug-15 A.Ribon migrating to G4Exp, G4Log 36 // 06-Aug-15 A.Ribon migrating to G4Exp, G4Log and G4Pow 34 // 37 // 35 38 36 #include "G4ChargeExchange.hh" 39 #include "G4ChargeExchange.hh" 37 #include "G4ChargeExchangeXS.hh" << 38 #include "G4PhysicalConstants.hh" 40 #include "G4PhysicalConstants.hh" 39 #include "G4SystemOfUnits.hh" 41 #include "G4SystemOfUnits.hh" 40 #include "G4ParticleTable.hh" 42 #include "G4ParticleTable.hh" 41 #include "G4ParticleDefinition.hh" 43 #include "G4ParticleDefinition.hh" 42 #include "G4IonTable.hh" 44 #include "G4IonTable.hh" 43 #include "Randomize.hh" 45 #include "Randomize.hh" 44 #include "G4NucleiProperties.hh" 46 #include "G4NucleiProperties.hh" 45 #include "G4DecayTable.hh" << 46 #include "G4VDecayChannel.hh" << 47 #include "G4DecayProducts.hh" << 48 #include "G4NistManager.hh" << 49 #include "G4Fragment.hh" << 50 #include "G4ExcitationHandler.hh" << 51 #include "G4ReactionProductVector.hh" << 52 47 53 #include "G4Exp.hh" 48 #include "G4Exp.hh" 54 #include "G4Log.hh" 49 #include "G4Log.hh" 55 #include "G4Pow.hh" 50 #include "G4Pow.hh" 56 51 57 #include "G4HadronicParameters.hh" 52 #include "G4HadronicParameters.hh" 58 #include "G4PhysicsModelCatalog.hh" 53 #include "G4PhysicsModelCatalog.hh" 59 54 60 namespace << 61 { << 62 constexpr G4int maxN = 1000; << 63 constexpr G4double emin = 2*136.9*CLHEP::MeV << 64 } << 65 55 66 G4ChargeExchange::G4ChargeExchange(G4ChargeExc << 56 G4ChargeExchange::G4ChargeExchange() : G4HadronicInteraction("Charge Exchange"), secID(-1) 67 : G4HadronicInteraction("ChargeExchange"), << 68 fXSection(ptr), fXSWeightFactor(1.0) << 69 { 57 { 70 lowEnergyLimit = 1.*CLHEP::MeV; << 58 SetMinEnergy( 0.0*GeV ); >> 59 SetMaxEnergy( G4HadronicParameters::Instance()->GetMaxEnergy() ); >> 60 >> 61 lowestEnergyLimit = 1.*MeV; >> 62 >> 63 theProton = G4Proton::Proton(); >> 64 theNeutron = G4Neutron::Neutron(); >> 65 theAProton = G4AntiProton::AntiProton(); >> 66 theANeutron = G4AntiNeutron::AntiNeutron(); >> 67 thePiPlus = G4PionPlus::PionPlus(); >> 68 thePiMinus = G4PionMinus::PionMinus(); >> 69 thePiZero = G4PionZero::PionZero(); >> 70 theKPlus = G4KaonPlus::KaonPlus(); >> 71 theKMinus = G4KaonMinus::KaonMinus(); >> 72 theK0S = G4KaonZeroShort::KaonZeroShort(); >> 73 theK0L = G4KaonZeroLong::KaonZeroLong(); >> 74 theL = G4Lambda::Lambda(); >> 75 theAntiL = G4AntiLambda::AntiLambda(); >> 76 theSPlus = G4SigmaPlus::SigmaPlus(); >> 77 theASPlus = G4AntiSigmaPlus::AntiSigmaPlus(); >> 78 theSMinus = G4SigmaMinus::SigmaMinus(); >> 79 theASMinus = G4AntiSigmaMinus::AntiSigmaMinus(); >> 80 theS0 = G4SigmaZero::SigmaZero(); >> 81 theAS0 = G4AntiSigmaZero::AntiSigmaZero(); >> 82 theXiMinus = G4XiMinus::XiMinus(); >> 83 theXi0 = G4XiZero::XiZero(); >> 84 theAXiMinus = G4AntiXiMinus::AntiXiMinus(); >> 85 theAXi0 = G4AntiXiZero::AntiXiZero(); >> 86 theOmega = G4OmegaMinus::OmegaMinus(); >> 87 theAOmega = G4AntiOmegaMinus::AntiOmegaMinus(); >> 88 theD = G4Deuteron::Deuteron(); >> 89 theT = G4Triton::Triton(); >> 90 theA = G4Alpha::Alpha(); >> 91 theHe3 = G4He3::He3(); >> 92 71 secID = G4PhysicsModelCatalog::GetModelID( " 93 secID = G4PhysicsModelCatalog::GetModelID( "model_ChargeExchange" ); 72 nist = G4NistManager::Instance(); << 73 fHandler = new G4ExcitationHandler(); << 74 if (nullptr != fXSection) { << 75 fXSWeightFactor = 1.0/fXSection->GetCrossS << 76 } << 77 } 94 } 78 95 79 G4ChargeExchange::~G4ChargeExchange() 96 G4ChargeExchange::~G4ChargeExchange() 80 { << 97 {} 81 delete fHandler; << 82 } << 83 98 84 G4HadFinalState* G4ChargeExchange::ApplyYourse 99 G4HadFinalState* G4ChargeExchange::ApplyYourself( 85 const G4HadProjectile& aTrack, G4Nucleus& 100 const G4HadProjectile& aTrack, G4Nucleus& targetNucleus) 86 { 101 { 87 theParticleChange.Clear(); 102 theParticleChange.Clear(); 88 auto part = aTrack.GetDefinition(); << 103 const G4HadProjectile* aParticle = &aTrack; 89 G4double ekin = aTrack.GetKineticEnergy(); << 104 G4double ekin = aParticle->GetKineticEnergy(); 90 105 91 G4int A = targetNucleus.GetA_asInt(); 106 G4int A = targetNucleus.GetA_asInt(); 92 G4int Z = targetNucleus.GetZ_asInt(); 107 G4int Z = targetNucleus.GetZ_asInt(); 93 108 94 if (ekin <= lowEnergyLimit) { << 109 if(ekin <= lowestEnergyLimit || A < 3) { >> 110 theParticleChange.SetEnergyChange(ekin); >> 111 theParticleChange.SetMomentumChange(0.0,0.0,1.0); 95 return &theParticleChange; 112 return &theParticleChange; 96 } 113 } 97 theParticleChange.SetWeightChange(fXSWeightF << 98 114 99 G4int projPDG = part->GetPDGEncoding(); << 115 G4double plab = aParticle->GetTotalMomentum(); 100 116 101 // for hydrogen targets and positive project << 102 // is not possible on proton, only on deuter << 103 if (1 == Z && (211 == projPDG || 321 == proj << 104 << 105 if (verboseLevel > 1) 117 if (verboseLevel > 1) 106 G4cout << "G4ChargeExchange for " << part- << 118 G4cout << "G4ChargeExchange::DoIt: Incident particle plab=" >> 119 << plab/GeV << " GeV/c " >> 120 << " ekin(MeV) = " << ekin/MeV << " " >> 121 << aParticle->GetDefinition()->GetParticleName() << G4endl; >> 122 >> 123 // Scattered particle referred to axis of incident particle >> 124 const G4ParticleDefinition* theParticle = aParticle->GetDefinition(); >> 125 >> 126 G4int N = A - Z; >> 127 G4int projPDG = theParticle->GetPDGEncoding(); >> 128 if (verboseLevel > 1) >> 129 G4cout << "G4ChargeExchange for " << theParticle->GetParticleName() 107 << " PDGcode= " << projPDG << " on nucleu 130 << " PDGcode= " << projPDG << " on nucleus Z= " << Z 108 << " A= " << A << " N= " << A - Z << 131 << " A= " << A << " N= " << N 109 << G4endl; 132 << G4endl; 110 133 111 G4double mass1 = G4NucleiProperties::GetNucl << 134 const G4ParticleDefinition* theDef = nullptr; 112 G4LorentzVector lv0 = aTrack.Get4Momentum(); << 113 G4double etot = mass1 + lv0.e(); << 114 << 115 // select final state << 116 const G4ParticleDefinition* theSecondary = << 117 fXSection->SampleSecondaryType(part, Z, A) << 118 G4int pdg = theSecondary->GetPDGEncoding(); << 119 << 120 // omega(782) and f2(1270) << 121 G4bool isShortLived = (pdg == 223 || pdg == << 122 << 123 // atomic number of the recoil nucleus << 124 if (projPDG == -211) { --Z; } << 125 else if (projPDG == 211) { ++Z; } << 126 else if (projPDG == -321) { --Z; } << 127 else if (projPDG == 321) { ++Z; } << 128 else if (projPDG == 130) { << 129 if (theSecondary->GetPDGCharge() > 0.0) { << 130 else { ++Z; } << 131 } else { << 132 // not ready for other projectile << 133 return &theParticleChange; << 134 } << 135 135 136 // recoil nucleus << 136 G4double mass2 = G4NucleiProperties::GetNuclearMass(A, Z); >> 137 G4LorentzVector lv1 = aParticle->Get4Momentum(); >> 138 G4LorentzVector lv0(0.0,0.0,0.0,mass2); >> 139 >> 140 G4LorentzVector lv = lv0 + lv1; >> 141 G4ThreeVector bst = lv.boostVector(); >> 142 lv1.boost(-bst); >> 143 lv0.boost(-bst); >> 144 >> 145 // Sample final particles >> 146 G4bool theHyperon = false; 137 const G4ParticleDefinition* theRecoil = null 147 const G4ParticleDefinition* theRecoil = nullptr; 138 if (Z == 0 && A == 1) { theRecoil = G4Neutro << 148 const G4ParticleDefinition* theSecondary = nullptr; 139 else if (Z == 1 && A == 1) { theRecoil = G4P << 140 else if (Z == 1 && A == 2) { theRecoil = G4D << 141 else if (Z == 1 && A == 3) { theRecoil = G4T << 142 else if (Z == 2 && A == 3) { theRecoil = G4H << 143 else if (Z == 2 && A == 4) { theRecoil = G4A << 144 else if (nist->GetIsotopeAbundance(Z, A) > 0 << 145 theRecoil = G4ParticleTable::GetParticleTa << 146 ->GetIonTable()->GetIon(Z, A, 0.0); << 147 } << 148 149 149 // check if there is enough energy for the f << 150 if(theParticle == theProton) { 150 // and sample mass of produced state << 151 theSecondary = theNeutron; 151 const G4double mass0 = theSecondary->GetPDGM << 152 Z++; 152 G4double mass3 = (nullptr == theRecoil) ? << 153 } else if(theParticle == theNeutron) { 153 G4NucleiProperties::GetNuclearMass(A, Z) : << 154 theSecondary = theProton; 154 G4double mass2 = mass0; << 155 Z--; 155 if (isShortLived && << 156 } else if(theParticle == thePiPlus) { 156 !SampleMass(mass2, theSecondary->GetPDGW << 157 theSecondary = thePiZero; 157 return &theParticleChange; << 158 Z++; >> 159 } else if(theParticle == thePiMinus) { >> 160 theSecondary = thePiZero; >> 161 Z--; >> 162 } else if(theParticle == theKPlus) { >> 163 if(G4UniformRand()<0.5) theSecondary = theK0S; >> 164 else theSecondary = theK0L; >> 165 Z++; >> 166 } else if(theParticle == theKMinus) { >> 167 if(G4UniformRand()<0.5) theSecondary = theK0S; >> 168 else theSecondary = theK0L; >> 169 Z--; >> 170 } else if(theParticle == theK0S || theParticle == theK0L) { >> 171 if(G4UniformRand()*A < G4double(Z)) { >> 172 theSecondary = theKPlus; >> 173 Z--; >> 174 } else { >> 175 theSecondary = theKMinus; >> 176 Z++; >> 177 } >> 178 } else if(theParticle == theANeutron) { >> 179 theSecondary = theAProton; >> 180 Z++; >> 181 } else if(theParticle == theAProton) { >> 182 theSecondary = theANeutron; >> 183 Z--; >> 184 } else if(theParticle == theL) { >> 185 G4double x = G4UniformRand(); >> 186 if(G4UniformRand()*A < G4double(Z)) { >> 187 if(x < 0.2) { >> 188 theSecondary = theS0; >> 189 } else if (x < 0.4) { >> 190 theSecondary = theSPlus; >> 191 Z--; >> 192 } else if (x < 0.6) { >> 193 theSecondary = theProton; >> 194 theRecoil = theL; >> 195 theHyperon = true; >> 196 A--; >> 197 } else if (x < 0.8) { >> 198 theSecondary = theProton; >> 199 theRecoil = theS0; >> 200 theHyperon = true; >> 201 A--; >> 202 } else { >> 203 theSecondary = theNeutron; >> 204 theRecoil = theSPlus; >> 205 theHyperon = true; >> 206 A--; >> 207 } >> 208 } else { >> 209 if(x < 0.2) { >> 210 theSecondary = theS0; >> 211 } else if (x < 0.4) { >> 212 theSecondary = theSMinus; >> 213 Z++; >> 214 } else if (x < 0.6) { >> 215 theSecondary = theNeutron; >> 216 theRecoil = theL; >> 217 A--; >> 218 theHyperon = true; >> 219 } else if (x < 0.8) { >> 220 theSecondary = theNeutron; >> 221 theRecoil = theS0; >> 222 theHyperon = true; >> 223 A--; >> 224 } else { >> 225 theSecondary = theProton; >> 226 theRecoil = theSMinus; >> 227 theHyperon = true; >> 228 A--; >> 229 } >> 230 } 158 } 231 } 159 232 160 // not possible kinematically << 233 if (Z == 1 && A == 2) theDef = theD; 161 if (etot <= mass2 + mass3) { << 234 else if (Z == 1 && A == 3) theDef = theT; >> 235 else if (Z == 2 && A == 3) theDef = theHe3; >> 236 else if (Z == 2 && A == 4) theDef = theA; >> 237 else { >> 238 theDef = >> 239 G4ParticleTable::GetParticleTable()->GetIonTable()->GetIon(Z,A,0.0); >> 240 } >> 241 if(!theSecondary) { return &theParticleChange; } >> 242 >> 243 G4double m11 = theSecondary->GetPDGMass(); >> 244 G4double m21 = theDef->GetPDGMass(); >> 245 if(theRecoil) { m21 += theRecoil->GetPDGMass(); } >> 246 else { theRecoil = theDef; } >> 247 >> 248 G4double etot = lv0.e() + lv1.e(); >> 249 >> 250 // kinematiacally impossible >> 251 if(etot < m11 + m21) { >> 252 theParticleChange.SetEnergyChange(ekin); >> 253 theParticleChange.SetMomentumChange(0.0,0.0,1.0); 162 return &theParticleChange; 254 return &theParticleChange; 163 } 255 } 164 256 165 // sample kinematics << 257 G4ThreeVector p1 = lv1.vect(); 166 G4LorentzVector lv1(0.0, 0.0, 0.0, mass1); << 258 G4double e1 = 0.5*etot*(1.0 - (m21*m21 - m11*m11)/(etot*etot)); 167 G4LorentzVector lv = lv0 + lv1; << 259 // G4double e2 = etot - e1; 168 G4ThreeVector bst = lv.boostVector(); << 260 G4double ptot = std::sqrt(e1*e1 - m11*m11); 169 G4double ss = lv.mag2(); << 261 170 << 262 G4double tmax = 4.0*ptot*ptot; 171 // tmax = 4*momCMS^2 << 263 G4double g2 = GeV*GeV; 172 G4double e2 = ss + mass2*mass2 - mass3*mass3 << 264 173 G4double tmax = e2*e2/ss - 4*mass2*mass2; << 265 G4double t = g2*SampleT(tmax/g2, A); 174 << 266 175 G4double t = SampleT(theSecondary, A, tmax); << 267 if(verboseLevel>1) { 176 << 268 G4cout <<"## G4ChargeExchange t= " << t << " tmax= " << tmax 177 G4double phi = G4UniformRand()*CLHEP::twopi << 269 << " ptot= " << ptot << G4endl; >> 270 } >> 271 // Sampling in CM system >> 272 G4double phi = G4UniformRand()*twopi; 178 G4double cost = 1. - 2.0*t/tmax; 273 G4double cost = 1. - 2.0*t/tmax; >> 274 if(std::abs(cost) > 1.0) cost = 1.0; >> 275 G4double sint = std::sqrt((1.0-cost)*(1.0+cost)); 179 276 180 if (cost > 1.0) { cost = 1.0; } << 277 //if (verboseLevel > 1) 181 else if(cost < -1.0) { cost = -1.0; } << 278 // G4cout << "cos(t)=" << cost << " std::sin(t)=" << sint << G4endl; 182 279 183 G4double sint = std::sqrt((1.0-cost)*(1.0+co << 280 G4ThreeVector v1(sint*std::cos(phi),sint*std::sin(phi),cost); >> 281 v1 *= ptot; >> 282 G4LorentzVector nlv1(v1.x(),v1.y(),v1.z(),e1); >> 283 G4LorentzVector nlv0 = lv0 + lv1 - nlv1; 184 284 185 if (verboseLevel>1) { << 285 nlv0.boost(bst); 186 G4cout << " t= " << t << " tmax(GeV^2)= " << 286 nlv1.boost(bst); 187 << " cos(t)=" << cost << " sin(t)=" << si << 188 } << 189 G4double momentumCMS = 0.5*std::sqrt(tmax); << 190 G4LorentzVector lv2(momentumCMS*sint*std::co << 191 momentumCMS*sint*std::sin(phi), << 192 momentumCMS*cost, << 193 std::sqrt(momentumCMS*momentumCMS + << 194 << 195 // kinematics in the final state, may be a w << 196 lv2.boost(bst); << 197 if (lv2.e() < mass2) { << 198 lv2.setE(mass2); << 199 } << 200 lv -= lv2; << 201 if (lv.e() < mass3) { << 202 lv.setE(mass3); << 203 } << 204 287 205 // prepare secondary particles << 206 theParticleChange.SetStatusChange(stopAndKil 288 theParticleChange.SetStatusChange(stopAndKill); 207 theParticleChange.SetEnergyChange(0.0); 289 theParticleChange.SetEnergyChange(0.0); >> 290 G4DynamicParticle * aSec = new G4DynamicParticle(theSecondary, nlv1); >> 291 theParticleChange.AddSecondary(aSec, secID); 208 292 209 if (!isShortLived) { << 293 G4double erec = std::max(nlv0.e() - m21, 0.0); 210 auto aSec = new G4DynamicParticle(theSecon << 294 >> 295 //G4cout << "erec= " <<erec << " Esec= " << aSec->GetKineticEnergy() << G4endl; >> 296 >> 297 if(theHyperon) { >> 298 theParticleChange.SetLocalEnergyDeposit(erec); >> 299 aSec = new G4DynamicParticle(); >> 300 aSec->SetDefinition(theRecoil); >> 301 aSec->SetKineticEnergy(0.0); >> 302 } else if(erec > GetRecoilEnergyThreshold()) { >> 303 aSec = new G4DynamicParticle(theRecoil, nlv0); 211 theParticleChange.AddSecondary(aSec, secID 304 theParticleChange.AddSecondary(aSec, secID); 212 } else { 305 } else { 213 auto channel = theSecondary->GetDecayTable << 306 theParticleChange.SetLocalEnergyDeposit(erec); 214 auto products = channel->DecayIt(mass2); << 215 G4ThreeVector bst1 = lv2.boostVector(); << 216 G4int N = products->entries(); << 217 for (G4int i=0; i<N; ++i) { << 218 auto p = (*products)[i]; << 219 auto lvp = p->Get4Momentum(); << 220 lvp.boost(bst1); << 221 p->Set4Momentum(lvp); << 222 theParticleChange.AddSecondary(p, secID) << 223 } << 224 delete products; << 225 } << 226 << 227 // recoil is a stable isotope << 228 if (nullptr != theRecoil) { << 229 auto aRec = new G4DynamicParticle(theRecoi << 230 theParticleChange.AddSecondary(aRec, secID << 231 } else { << 232 // recoil is an unstable fragment << 233 G4Fragment frag(A, Z, lv); << 234 auto products = fHandler->BreakItUp(frag); << 235 for (auto & prod : *products) { << 236 auto dp = new G4DynamicParticle(prod->Ge << 237 theParticleChange.AddSecondary(dp, secID << 238 delete prod; << 239 } << 240 delete products; << 241 } 307 } 242 return &theParticleChange; 308 return &theParticleChange; 243 } 309 } 244 310 245 G4double G4ChargeExchange::SampleT(const G4Par << 311 G4double G4ChargeExchange::SampleT(G4double tmax, G4int A) 246 const G4int << 247 { 312 { 248 G4double aa, bb, cc, dd; 313 G4double aa, bb, cc, dd; 249 G4Pow* g4pow = G4Pow::GetInstance(); 314 G4Pow* g4pow = G4Pow::GetInstance(); 250 if (A <= 62.) { 315 if (A <= 62.) { 251 aa = g4pow->powZ(A, 1.63); 316 aa = g4pow->powZ(A, 1.63); 252 bb = 14.5*g4pow->powZ(A, 0.66); 317 bb = 14.5*g4pow->powZ(A, 0.66); 253 cc = 1.4*g4pow->powZ(A, 0.33); 318 cc = 1.4*g4pow->powZ(A, 0.33); 254 dd = 10.; 319 dd = 10.; 255 } else { 320 } else { 256 aa = g4pow->powZ(A, 1.33); 321 aa = g4pow->powZ(A, 1.33); 257 bb = 60.*g4pow->powZ(A, 0.33); 322 bb = 60.*g4pow->powZ(A, 0.33); 258 cc = 0.4*g4pow->powZ(A, 0.40); 323 cc = 0.4*g4pow->powZ(A, 0.40); 259 dd = 10.; 324 dd = 10.; 260 } 325 } 261 G4double x1 = (1.0 - G4Exp(-tmax*bb))*aa/bb; 326 G4double x1 = (1.0 - G4Exp(-tmax*bb))*aa/bb; 262 G4double x2 = (1.0 - G4Exp(-tmax*dd))*cc/dd; 327 G4double x2 = (1.0 - G4Exp(-tmax*dd))*cc/dd; 263 328 264 G4double t; 329 G4double t; 265 G4double y = bb; 330 G4double y = bb; 266 if(G4UniformRand()*(x1 + x2) < x2) y = dd; 331 if(G4UniformRand()*(x1 + x2) < x2) y = dd; 267 332 268 for (G4int i=0; i<maxN; ++i) { << 333 const G4int maxNumberOfLoops = 10000; >> 334 G4int loopCounter = 0; >> 335 do { 269 t = -G4Log(G4UniformRand())/y; 336 t = -G4Log(G4UniformRand())/y; 270 if (t <= tmax) { return t; } << 337 } while ( (t > tmax) && >> 338 ++loopCounter < maxNumberOfLoops ); /* Loop checking, 10.08.2015, A.Ribon */ >> 339 if ( loopCounter >= maxNumberOfLoops ) { >> 340 t = 0.0; 271 } 341 } 272 return 0.0; << 342 return t; 273 } 343 } 274 344 275 G4bool G4ChargeExchange::SampleMass(G4double& << 276 { << 277 // +- 4 width but above 2 pion mass << 278 const G4double e1 = std::max(M - 4*G, emin); << 279 const G4double e2 = std::min(M + 4*G, elim) << 280 if (e2 <= 0.0) { return false; } << 281 const G4double M2 = M*M; << 282 const G4double MG2 = M2*G*G; << 283 << 284 // sampling Breit-Wigner function << 285 for (G4int i=0; i<maxN; ++i) { << 286 G4double e = e1 + e2*G4UniformRand(); << 287 G4double x = e*e - M2; << 288 G4double y = MG2/(x*x + MG2); << 289 if (y >= G4UniformRand()) { << 290 M = e; << 291 return true; << 292 } << 293 } << 294 return false; << 295 } << 296 345