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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 // G4MuonDecayChannelWithSpin class implementa << 26 // ------------------------------------------------------------ >> 27 // GEANT 4 class header file >> 28 // >> 29 // History: >> 30 // 17 August 2004 P.Gumplinger and T.MacPhail >> 31 // samples Michel spectrum including 1st order >> 32 // radiative corrections >> 33 // Reference: Florian Scheck "Muon Physics", in Physics Reports >> 34 // (Review Section of Physics Letters) 44, No. 4 (1978) >> 35 // 187-248. North-Holland Publishing Company, Amsterdam >> 36 // at page 210 cc. >> 37 // >> 38 // W.E. Fisher and F. Scheck, Nucl. Phys. B83 (1974) 25. >> 39 // >> 40 // ------------------------------------------------------------ 27 // 41 // 28 // References: << 29 // - Florian Scheck "Muon Physics", in Physics << 30 // (Review Section of Physics Letters) 44, N << 31 // 187-248. North-Holland Publishing Company << 32 // - W.E. Fisher and F. Scheck, Nucl. Phys. B8 << 33 << 34 // Authors: P.Gumplinger and T.MacPhail, 17 Au << 35 // ------------------------------------------- << 36 << 37 #include "G4MuonDecayChannelWithSpin.hh" 42 #include "G4MuonDecayChannelWithSpin.hh" 38 43 39 #include "G4DecayProducts.hh" << 40 #include "G4LorentzVector.hh" << 41 #include "G4PhysicalConstants.hh" 44 #include "G4PhysicalConstants.hh" 42 #include "G4SystemOfUnits.hh" 45 #include "G4SystemOfUnits.hh" 43 #include "Randomize.hh" 46 #include "Randomize.hh" 44 47 45 G4MuonDecayChannelWithSpin::G4MuonDecayChannel << 48 #include "G4DecayProducts.hh" 46 << 49 #include "G4LorentzVector.hh" 47 : G4MuonDecayChannel(theParentName, theBR) << 50 48 {} << 51 G4MuonDecayChannelWithSpin::G4MuonDecayChannelWithSpin() >> 52 : G4MuonDecayChannel(), >> 53 parent_polarization(), >> 54 EMMU( 0.*MeV), >> 55 EMASS( 0.*MeV) >> 56 { >> 57 } >> 58 >> 59 G4MuonDecayChannelWithSpin::G4MuonDecayChannelWithSpin(const G4String& theParentName, >> 60 G4double theBR) >> 61 : G4MuonDecayChannel(theParentName,theBR), >> 62 parent_polarization(), >> 63 EMMU( 0.*MeV), >> 64 EMASS( 0.*MeV) >> 65 { >> 66 } 49 67 50 G4MuonDecayChannelWithSpin& << 68 G4MuonDecayChannelWithSpin::~G4MuonDecayChannelWithSpin() 51 G4MuonDecayChannelWithSpin::operator=(const G4 << 52 { 69 { 53 if (this != &right) { << 70 } >> 71 >> 72 G4MuonDecayChannelWithSpin::G4MuonDecayChannelWithSpin(const G4MuonDecayChannelWithSpin &right): >> 73 G4MuonDecayChannel(right) >> 74 { >> 75 parent_polarization = right.parent_polarization; >> 76 EMMU = right.EMMU; >> 77 EMASS = right.EMASS; >> 78 } >> 79 >> 80 G4MuonDecayChannelWithSpin & G4MuonDecayChannelWithSpin::operator=(const G4MuonDecayChannelWithSpin & right) >> 81 { >> 82 if (this != &right) { 54 kinematics_name = right.kinematics_name; 83 kinematics_name = right.kinematics_name; 55 verboseLevel = right.verboseLevel; 84 verboseLevel = right.verboseLevel; 56 rbranch = right.rbranch; 85 rbranch = right.rbranch; 57 86 58 // copy parent name 87 // copy parent name 59 delete parent_name; << 60 parent_name = new G4String(*right.parent_n 88 parent_name = new G4String(*right.parent_name); 61 89 62 // clear daughters_name array 90 // clear daughters_name array 63 ClearDaughtersName(); 91 ClearDaughtersName(); 64 92 65 // recreate array 93 // recreate array 66 numberOfDaughters = right.numberOfDaughter 94 numberOfDaughters = right.numberOfDaughters; 67 if (numberOfDaughters > 0) { << 95 if ( numberOfDaughters >0 ) { >> 96 if (daughters_name !=0) ClearDaughtersName(); 68 daughters_name = new G4String*[numberOfD 97 daughters_name = new G4String*[numberOfDaughters]; 69 // copy daughters name << 98 //copy daughters name 70 for (G4int index = 0; index < numberOfDa << 99 for (G4int index=0; index < numberOfDaughters; index++) { 71 daughters_name[index] = new G4String(* << 100 daughters_name[index] = new G4String(*right.daughters_name[index]); 72 } 101 } 73 } 102 } >> 103 parent_polarization = right.parent_polarization; >> 104 EMMU = right.EMMU; >> 105 EMASS = right.EMASS; 74 } 106 } 75 return *this; 107 return *this; 76 } 108 } 77 109 78 G4DecayProducts* G4MuonDecayChannelWithSpin::D << 110 >> 111 G4DecayProducts *G4MuonDecayChannelWithSpin::DecayIt(G4double) 79 { 112 { 80 // This version assumes V-A coupling with 1s 113 // This version assumes V-A coupling with 1st order radiative correctons, 81 // the standard model Michel pa 114 // the standard model Michel parameter values, but 82 // gives incorrect energy spect 115 // gives incorrect energy spectrum for neutrinos 83 116 84 #ifdef G4VERBOSE 117 #ifdef G4VERBOSE 85 if (GetVerboseLevel() > 1) G4cout << "G4Muon << 118 if (GetVerboseLevel()>1) G4cout << "G4MuonDecayChannelWithSpin::DecayIt "; 86 #endif 119 #endif 87 120 88 CheckAndFillParent(); << 121 if (G4MT_parent == 0) FillParent(); 89 CheckAndFillDaughters(); << 122 if (G4MT_daughters == 0) FillDaughters(); 90 123 91 // parent mass 124 // parent mass 92 G4double parentmass = G4MT_parent->GetPDGMas 125 G4double parentmass = G4MT_parent->GetPDGMass(); 93 126 94 G4double EMMU = parentmass; << 127 EMMU = parentmass; 95 128 96 // daughters'mass << 129 //daughters'mass 97 G4double daughtermass[3]; << 130 G4double daughtermass[3]; 98 // G4double sumofdaughtermass = 0.0; << 131 G4double sumofdaughtermass = 0.0; 99 for (G4int index = 0; index < 3; ++index) { << 132 for (G4int index=0; index<3; index++){ 100 daughtermass[index] = G4MT_daughters[index 133 daughtermass[index] = G4MT_daughters[index]->GetPDGMass(); 101 // sumofdaughtermass += daughtermass[index << 134 sumofdaughtermass += daughtermass[index]; 102 } 135 } 103 136 104 G4double EMASS = daughtermass[0]; << 137 EMASS = daughtermass[0]; 105 138 106 // create parent G4DynamicParticle at rest << 139 //create parent G4DynamicParticle at rest 107 G4ThreeVector dummy; 140 G4ThreeVector dummy; 108 auto parentparticle = new G4DynamicParticle( << 141 G4DynamicParticle * parentparticle = new G4DynamicParticle( G4MT_parent, dummy, 0.0); 109 // create G4Decayproducts << 142 //create G4Decayproducts 110 auto products = new G4DecayProducts(*parentp << 143 G4DecayProducts *products = new G4DecayProducts(*parentparticle); 111 delete parentparticle; 144 delete parentparticle; 112 145 113 // calculate electron energy << 146 // calcurate electron energy 114 147 115 G4double michel_rho = 0.75; // Standard Mod << 148 G4double michel_rho = 0.75; //Standard Model Michel rho 116 G4double michel_delta = 0.75; // Standard M << 149 G4double michel_delta = 0.75; //Standard Model Michel delta 117 G4double michel_xsi = 1.00; // Standard Mod << 150 G4double michel_xsi = 1.00; //Standard Model Michel xsi 118 G4double michel_eta = 0.00; // Standard Mod << 151 G4double michel_eta = 0.00; //Standard Model eta 119 152 120 G4double rndm, x, ctheta; 153 G4double rndm, x, ctheta; 121 154 122 G4double FG; << 155 G4double FG; 123 G4double FG_max = 2.00; 156 G4double FG_max = 2.00; 124 157 125 G4double W_mue = (EMMU * EMMU + EMASS * EMAS << 158 G4double W_mue = (EMMU*EMMU+EMASS*EMASS)/(2.*EMMU); 126 G4double x0 = EMASS / W_mue; << 159 G4double x0 = EMASS/W_mue; 127 160 128 G4double x0_squared = x0 * x0; << 161 G4double x0_squared = x0*x0; 129 162 130 // ***************************************** 163 // *************************************************** 131 // x0 <= x <= 1. and -1 <= y <= 1 164 // x0 <= x <= 1. and -1 <= y <= 1 132 // 165 // 133 // F(x,y) = f(x)*g(x,y); g(x,y) = 1.+g 166 // F(x,y) = f(x)*g(x,y); g(x,y) = 1.+g(x)*y 134 // ***************************************** 167 // *************************************************** 135 168 136 // ***** sampling F(x,y) directly (brute for 169 // ***** sampling F(x,y) directly (brute force) ***** 137 170 138 const std::size_t MAX_LOOP = 10000; << 171 do{ 139 for (std::size_t loop_count = 0; loop_count << 172 140 // Sample the positron energy by sampling 173 // Sample the positron energy by sampling from F 141 174 142 rndm = G4UniformRand(); 175 rndm = G4UniformRand(); 143 176 144 x = x0 + rndm * (1. - x0); << 177 x = x0 + rndm*(1.-x0); 145 178 146 G4double x_squared = x * x; << 179 G4double x_squared = x*x; 147 180 148 G4double F_IS, F_AS, G_IS, G_AS; 181 G4double F_IS, F_AS, G_IS, G_AS; 149 182 150 F_IS = 1. / 6. * (-2. * x_squared + 3. * x << 183 F_IS = 1./6.*(-2.*x_squared+3.*x-x0_squared); 151 F_AS = 1. / 6. * std::sqrt(x_squared - x0_ << 184 F_AS = 1./6.*std::sqrt(x_squared-x0_squared)*(2.*x-2.+std::sqrt(1.-x0_squared)); 152 185 153 G_IS = 2. / 9. * (michel_rho - 0.75) * (4. << 186 G_IS = 2./9.*(michel_rho-0.75)*(4.*x_squared-3.*x-x0_squared); 154 G_IS = G_IS + michel_eta * (1. - x) * x0; << 187 G_IS = G_IS + michel_eta*(1.-x)*x0; 155 188 156 G_AS = 3. * (michel_xsi - 1.) * (1. - x); << 189 G_AS = 3.*(michel_xsi-1.)*(1.-x); 157 G_AS = << 190 G_AS = G_AS+2.*(michel_xsi*michel_delta-0.75)*(4.*x-4.+std::sqrt(1.-x0_squared)); 158 G_AS + 2. * (michel_xsi * michel_delta - << 191 G_AS = 1./9.*std::sqrt(x_squared-x0_squared)*G_AS; 159 G_AS = 1. / 9. * std::sqrt(x_squared - x0_ << 160 192 161 F_IS = F_IS + G_IS; 193 F_IS = F_IS + G_IS; 162 F_AS = F_AS + G_AS; 194 F_AS = F_AS + G_AS; 163 195 164 // *** Radiative Corrections *** 196 // *** Radiative Corrections *** 165 197 166 const G4double omega = std::log(EMMU / EMA << 198 G4double R_IS = F_c(x,x0); 167 G4double R_IS = F_c(x, x0, omega); << 168 199 169 G4double F = 6. * F_IS + R_IS / std::sqrt( << 200 G4double F = 6.*F_IS + R_IS/std::sqrt(x_squared-x0_squared); 170 201 171 // *** Radiative Corrections *** 202 // *** Radiative Corrections *** 172 203 173 G4double R_AS = F_theta(x, x0, omega); << 204 G4double R_AS = F_theta(x,x0); 174 205 175 rndm = G4UniformRand(); 206 rndm = G4UniformRand(); 176 207 177 ctheta = 2. * rndm - 1.; << 208 ctheta = 2.*rndm-1.; 178 209 179 G4double G = 6. * F_AS - R_AS / std::sqrt( << 210 G4double G = 6.*F_AS - R_AS/std::sqrt(x_squared-x0_squared); 180 211 181 FG = std::sqrt(x_squared - x0_squared) * F << 212 FG = std::sqrt(x_squared-x0_squared)*F*(1.+(G/F)*ctheta); 182 213 183 if (FG > FG_max) { << 214 if(FG>FG_max){ 184 G4Exception("G4MuonDecayChannelWithSpin: << 215 G4cout<<"***Problem in Muon Decay *** : FG > FG_max"<<G4endl; 185 "Problem in Muon Decay: FG > << 186 FG_max = FG; 216 FG_max = FG; 187 } 217 } 188 218 189 rndm = G4UniformRand(); 219 rndm = G4UniformRand(); 190 220 191 if (FG >= rndm * FG_max) break; << 221 }while(FG<rndm*FG_max); 192 } << 193 222 194 G4double energy = x * W_mue; 223 G4double energy = x * W_mue; 195 224 196 rndm = G4UniformRand(); 225 rndm = G4UniformRand(); 197 226 198 G4double phi = twopi * rndm; 227 G4double phi = twopi * rndm; 199 228 200 if (energy < EMASS) energy = EMASS; << 229 if(energy < EMASS) energy = EMASS; 201 230 202 // Calculate daughter momentum << 231 // calculate daughter momentum 203 G4double daughtermomentum[3]; 232 G4double daughtermomentum[3]; 204 233 205 daughtermomentum[0] = std::sqrt(energy * ene << 234 daughtermomentum[0] = std::sqrt(energy*energy - EMASS*EMASS); 206 235 207 G4double stheta = std::sqrt(1. - ctheta * ct << 236 G4double stheta = std::sqrt(1.-ctheta*ctheta); 208 G4double cphi = std::cos(phi); 237 G4double cphi = std::cos(phi); 209 G4double sphi = std::sin(phi); 238 G4double sphi = std::sin(phi); 210 239 211 // Coordinates of the decay positron with re << 240 //Coordinates of the decay positron with respect to the muon spin 212 G4double px = stheta * cphi; << 241 213 G4double py = stheta * sphi; << 242 G4double px = stheta*cphi; >> 243 G4double py = stheta*sphi; 214 G4double pz = ctheta; 244 G4double pz = ctheta; 215 245 216 G4ThreeVector direction0(px, py, pz); << 246 G4ThreeVector direction0(px,py,pz); 217 247 218 direction0.rotateUz(parent_polarization); 248 direction0.rotateUz(parent_polarization); 219 249 220 auto daughterparticle0 = << 250 G4DynamicParticle * daughterparticle0 221 new G4DynamicParticle(G4MT_daughters[0], d << 251 = new G4DynamicParticle( G4MT_daughters[0], daughtermomentum[0]*direction0); 222 252 223 products->PushProducts(daughterparticle0); 253 products->PushProducts(daughterparticle0); 224 254 >> 255 225 // daughter 1 ,2 (neutrinos) 256 // daughter 1 ,2 (neutrinos) 226 // create neutrinos in the C.M frame of two 257 // create neutrinos in the C.M frame of two neutrinos 227 G4double energy2 = parentmass - energy; << 258 G4double energy2 = parentmass*(1.0 - x/2.0); 228 G4double vmass = std::sqrt((energy2 - daught << 259 G4double vmass = std::sqrt((energy2-daughtermomentum[0])*(energy2+daughtermomentum[0])); 229 G4double beta = -1.0 * daughtermomentum[0] / << 260 G4double beta = -1.0*daughtermomentum[0]/energy2; 230 G4double costhetan = 2. * G4UniformRand() - << 261 G4double costhetan = 2.*G4UniformRand()-1.0; 231 G4double sinthetan = std::sqrt((1.0 - costhe << 262 G4double sinthetan = std::sqrt((1.0-costhetan)*(1.0+costhetan)); 232 G4double phin = twopi * G4UniformRand() * ra << 263 G4double phin = twopi*G4UniformRand()*rad; 233 G4double sinphin = std::sin(phin); 264 G4double sinphin = std::sin(phin); 234 G4double cosphin = std::cos(phin); 265 G4double cosphin = std::cos(phin); 235 266 236 G4ThreeVector direction1(sinthetan * cosphin << 267 G4ThreeVector direction1(sinthetan*cosphin,sinthetan*sinphin,costhetan); 237 auto daughterparticle1 = new G4DynamicPartic << 268 G4DynamicParticle * daughterparticle1 238 auto daughterparticle2 = << 269 = new G4DynamicParticle( G4MT_daughters[1], direction1*(vmass/2.)); 239 new G4DynamicParticle(G4MT_daughters[2], d << 270 G4DynamicParticle * daughterparticle2 >> 271 = new G4DynamicParticle( G4MT_daughters[2], direction1*(-1.0*vmass/2.)); 240 272 241 // boost to the muon rest frame 273 // boost to the muon rest frame 242 G4LorentzVector p4; 274 G4LorentzVector p4; 243 p4 = daughterparticle1->Get4Momentum(); 275 p4 = daughterparticle1->Get4Momentum(); 244 p4.boost(direction0.x() * beta, direction0.y << 276 p4.boost( direction0.x()*beta, direction0.y()*beta, direction0.z()*beta); 245 daughterparticle1->Set4Momentum(p4); 277 daughterparticle1->Set4Momentum(p4); 246 p4 = daughterparticle2->Get4Momentum(); 278 p4 = daughterparticle2->Get4Momentum(); 247 p4.boost(direction0.x() * beta, direction0.y << 279 p4.boost( direction0.x()*beta, direction0.y()*beta, direction0.z()*beta); 248 daughterparticle2->Set4Momentum(p4); 280 daughterparticle2->Set4Momentum(p4); 249 products->PushProducts(daughterparticle1); 281 products->PushProducts(daughterparticle1); 250 products->PushProducts(daughterparticle2); 282 products->PushProducts(daughterparticle2); 251 daughtermomentum[1] = daughterparticle1->Get 283 daughtermomentum[1] = daughterparticle1->GetTotalMomentum(); 252 daughtermomentum[2] = daughterparticle2->Get 284 daughtermomentum[2] = daughterparticle2->GetTotalMomentum(); 253 285 254 // output message 286 // output message 255 #ifdef G4VERBOSE 287 #ifdef G4VERBOSE 256 if (GetVerboseLevel() > 1) { << 288 if (GetVerboseLevel()>1) { 257 G4cout << "G4MuonDecayChannelWithSpin::Dec 289 G4cout << "G4MuonDecayChannelWithSpin::DecayIt "; 258 G4cout << " create decay products in rest << 290 G4cout << " create decay products in rest frame " <<G4endl; 259 G4double TT = daughterparticle0->GetTotalE << 291 products->DumpInfo(); 260 + daughterparticle2->GetTota << 261 G4cout << "e " << daughterparticle0->GetT << 262 G4cout << "nu1" << daughterparticle1->GetT << 263 G4cout << "nu2" << daughterparticle2->GetT << 264 G4cout << "total" << (TT - parentmass) / k << 265 if (GetVerboseLevel() > 2) { << 266 products->DumpInfo(); << 267 } << 268 } 292 } 269 #endif 293 #endif 270 << 271 return products; 294 return products; 272 } 295 } 273 296 274 G4double G4MuonDecayChannelWithSpin::R_c(G4dou << 297 G4double G4MuonDecayChannelWithSpin::R_c(G4double x){ 275 { << 298 276 auto n_max = (G4int)(100. * x); << 299 G4int n_max = (int)(100.*x); 277 300 278 if (n_max < 10) n_max = 10; << 301 if(n_max<10)n_max=10; 279 302 280 G4double L2 = 0.0; 303 G4double L2 = 0.0; 281 304 282 for (G4int n = 1; n <= n_max; ++n) { << 305 for(G4int n=1; n<=n_max; n++){ 283 L2 += std::pow(x, n) / (n * n); << 306 L2 += std::pow(x,n)/(n*n); 284 } 307 } 285 308 >> 309 G4double omega = std::log(EMMU/EMASS); >> 310 286 G4double r_c; 311 G4double r_c; 287 312 288 r_c = 2. * L2 - (pi * pi / 3.) - 2.; << 313 r_c = 2.*L2-(pi*pi/3.)-2.; 289 r_c = r_c + omega * (1.5 + 2. * std::log((1. << 314 r_c = r_c + omega * (1.5+2.*std::log((1.-x)/x)); 290 r_c = r_c - std::log(x) * (2. * std::log(x) << 315 r_c = r_c - std::log(x)*(2.*std::log(x)-1.); 291 r_c = r_c + (3. * std::log(x) - 1. - 1. / x) << 316 r_c = r_c + (3.*std::log(x)-1.-1./x)*std::log(1.-x); 292 317 293 return r_c; 318 return r_c; 294 } 319 } 295 320