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25 // 25 //
26 // G4TauLeptonicDecayChannel class implementat <<
27 // 26 //
28 // Author: H.Kurashige, 30 May 1997 << 27 //
29 // ------------------------------------------- << 28 //
30 << 29 // ------------------------------------------------------------
31 #include "G4TauLeptonicDecayChannel.hh" << 30 // GEANT 4 class header file
>> 31 //
>> 32 // History: first implementation, based on object model of
>> 33 // 30 May 1997 H.Kurashige
>> 34 //
>> 35 // Fix bug in calcuration of electron energy in DecayIt 28 Feb. 01 H.Kurashige
>> 36 // ------------------------------------------------------------
32 37
33 #include "G4DecayProducts.hh" <<
34 #include "G4LorentzRotation.hh" <<
35 #include "G4LorentzVector.hh" <<
36 #include "G4ParticleDefinition.hh" 38 #include "G4ParticleDefinition.hh"
37 #include "G4PhysicalConstants.hh" 39 #include "G4PhysicalConstants.hh"
38 #include "G4SystemOfUnits.hh" 40 #include "G4SystemOfUnits.hh"
>> 41 #include "G4DecayProducts.hh"
39 #include "G4VDecayChannel.hh" 42 #include "G4VDecayChannel.hh"
>> 43 #include "G4TauLeptonicDecayChannel.hh"
40 #include "Randomize.hh" 44 #include "Randomize.hh"
>> 45 #include "G4LorentzVector.hh"
>> 46 #include "G4LorentzRotation.hh"
>> 47
>> 48
>> 49 G4TauLeptonicDecayChannel::G4TauLeptonicDecayChannel()
>> 50 :G4VDecayChannel()
>> 51 {
>> 52 }
>> 53
41 54
42 G4TauLeptonicDecayChannel::G4TauLeptonicDecayC << 55 G4TauLeptonicDecayChannel::G4TauLeptonicDecayChannel(
43 << 56 const G4String& theParentName,
44 : G4VDecayChannel("Tau Leptonic Decay", 1) << 57 G4double theBR,
>> 58 const G4String& theLeptonName)
>> 59 :G4VDecayChannel("Tau Leptonic Decay",1)
45 { 60 {
46 // set names for daughter particles 61 // set names for daughter particles
47 if (theParentName == "tau+") { 62 if (theParentName == "tau+") {
48 SetBR(theBR); 63 SetBR(theBR);
49 SetParent("tau+"); 64 SetParent("tau+");
50 SetNumberOfDaughters(3); 65 SetNumberOfDaughters(3);
51 if ((theLeptonName == "e-" || theLeptonNam << 66 if ((theLeptonName=="e-"||theLeptonName=="e+")){
52 SetDaughter(0, "e+"); 67 SetDaughter(0, "e+");
53 SetDaughter(1, "nu_e"); 68 SetDaughter(1, "nu_e");
54 SetDaughter(2, "anti_nu_tau"); 69 SetDaughter(2, "anti_nu_tau");
55 } << 70 } else {
56 else { <<
57 SetDaughter(0, "mu+"); 71 SetDaughter(0, "mu+");
58 SetDaughter(1, "nu_mu"); 72 SetDaughter(1, "nu_mu");
59 SetDaughter(2, "anti_nu_tau"); 73 SetDaughter(2, "anti_nu_tau");
60 } << 74 }
61 } << 75 } else if (theParentName == "tau-") {
62 else if (theParentName == "tau-") { <<
63 SetBR(theBR); 76 SetBR(theBR);
64 SetParent("tau-"); 77 SetParent("tau-");
65 SetNumberOfDaughters(3); 78 SetNumberOfDaughters(3);
66 if ((theLeptonName == "e-" || theLeptonNam << 79 if ((theLeptonName=="e-"||theLeptonName=="e+")){
67 SetDaughter(0, "e-"); 80 SetDaughter(0, "e-");
68 SetDaughter(1, "anti_nu_e"); 81 SetDaughter(1, "anti_nu_e");
69 SetDaughter(2, "nu_tau"); 82 SetDaughter(2, "nu_tau");
70 } << 83 } else {
71 else { <<
72 SetDaughter(0, "mu-"); 84 SetDaughter(0, "mu-");
73 SetDaughter(1, "anti_nu_mu"); 85 SetDaughter(1, "anti_nu_mu");
74 SetDaughter(2, "nu_tau"); 86 SetDaughter(2, "nu_tau");
75 } << 87 }
76 } << 88 } else {
77 else { <<
78 #ifdef G4VERBOSE 89 #ifdef G4VERBOSE
79 if (GetVerboseLevel() > 0) { << 90 if (GetVerboseLevel()>0) {
80 G4cout << "G4TauLeptonicDecayChannel:: c 91 G4cout << "G4TauLeptonicDecayChannel:: constructor :";
81 G4cout << " parent particle is not tau b 92 G4cout << " parent particle is not tau but ";
82 G4cout << theParentName << G4endl; 93 G4cout << theParentName << G4endl;
83 } 94 }
84 #endif 95 #endif
85 } 96 }
86 } 97 }
87 98
88 G4TauLeptonicDecayChannel& << 99 G4TauLeptonicDecayChannel::~G4TauLeptonicDecayChannel()
89 G4TauLeptonicDecayChannel::operator=(const G4T << 100 {
>> 101 }
>> 102
>> 103 G4TauLeptonicDecayChannel::G4TauLeptonicDecayChannel(const G4TauLeptonicDecayChannel &right):
>> 104 G4VDecayChannel(right)
90 { 105 {
91 if (this != &right) { << 106 }
>> 107
>> 108 G4TauLeptonicDecayChannel & G4TauLeptonicDecayChannel::operator=(const G4TauLeptonicDecayChannel & right)
>> 109 {
>> 110 if (this != &right) {
92 kinematics_name = right.kinematics_name; 111 kinematics_name = right.kinematics_name;
93 verboseLevel = right.verboseLevel; 112 verboseLevel = right.verboseLevel;
94 rbranch = right.rbranch; 113 rbranch = right.rbranch;
95 114
96 // copy parent name 115 // copy parent name
97 parent_name = new G4String(*right.parent_n 116 parent_name = new G4String(*right.parent_name);
98 117
99 // clear daughters_name array 118 // clear daughters_name array
100 ClearDaughtersName(); 119 ClearDaughtersName();
101 120
102 // recreate array 121 // recreate array
103 numberOfDaughters = right.numberOfDaughter 122 numberOfDaughters = right.numberOfDaughters;
104 if (numberOfDaughters > 0) { << 123 if ( numberOfDaughters >0 ) {
105 if (daughters_name != nullptr) ClearDaug << 124 if (daughters_name !=0) ClearDaughtersName();
106 daughters_name = new G4String*[numberOfD 125 daughters_name = new G4String*[numberOfDaughters];
107 // copy daughters name << 126 //copy daughters name
108 for (G4int index = 0; index < numberOfDa << 127 for (G4int index=0; index < numberOfDaughters; index++) {
109 daughters_name[index] = new G4String(* << 128 daughters_name[index] = new G4String(*right.daughters_name[index]);
110 } 129 }
111 } 130 }
112 } 131 }
113 return *this; 132 return *this;
114 } 133 }
115 134
116 G4DecayProducts* G4TauLeptonicDecayChannel::De << 135 G4DecayProducts *G4TauLeptonicDecayChannel::DecayIt(G4double)
117 { 136 {
118 // this version neglects muon polarization << 137 // this version neglects muon polarization
119 // assumes the pure V-A couplin 138 // assumes the pure V-A coupling
120 // gives incorrect energy spect 139 // gives incorrect energy spectrum for neutrinos
121 <<
122 #ifdef G4VERBOSE 140 #ifdef G4VERBOSE
123 if (GetVerboseLevel() > 1) G4cout << "G4TauL << 141 if (GetVerboseLevel()>1) G4cout << "G4TauLeptonicDecayChannel::DecayIt ";
124 #endif 142 #endif
125 143
126 CheckAndFillParent(); 144 CheckAndFillParent();
127 CheckAndFillDaughters(); 145 CheckAndFillDaughters();
128 << 146
129 // parent mass 147 // parent mass
130 G4double parentmass = G4MT_parent->GetPDGMas 148 G4double parentmass = G4MT_parent->GetPDGMass();
131 149
132 // daughters'mass << 150 //daughters'mass
133 const G4int N_DAUGHTER = 3; << 151 const G4int N_DAUGHTER=3;
134 G4double daughtermass[N_DAUGHTER]; << 152 G4double daughtermass[N_DAUGHTER];
135 for (G4int index = 0; index < N_DAUGHTER; ++ << 153 for (G4int index=0; index<N_DAUGHTER; index++){
136 daughtermass[index] = G4MT_daughters[index 154 daughtermass[index] = G4MT_daughters[index]->GetPDGMass();
137 } 155 }
138 156
139 // create parent G4DynamicParticle at rest << 157 //create parent G4DynamicParticle at rest
140 G4ThreeVector dummy; 158 G4ThreeVector dummy;
141 auto parentparticle = new G4DynamicParticle( << 159 G4DynamicParticle * parentparticle = new G4DynamicParticle( G4MT_parent, dummy, 0.0);
142 // create G4Decayproducts << 160 //create G4Decayproducts
143 auto products = new G4DecayProducts(*parentp << 161 G4DecayProducts *products = new G4DecayProducts(*parentparticle);
144 delete parentparticle; 162 delete parentparticle;
145 163
146 // calculate daughter momentum 164 // calculate daughter momentum
147 G4double daughtermomentum[N_DAUGHTER]; 165 G4double daughtermomentum[N_DAUGHTER];
148 166
149 // calculate lepton momentum << 167 // calcurate lepton momentum
150 G4double pmax = (parentmass * parentmass - d << 168 G4double pmax = (parentmass*parentmass-daughtermass[0]*daughtermass[0])/2./parentmass;
151 G4double p, e; 169 G4double p, e;
152 G4double r; 170 G4double r;
153 const std::size_t MAX_LOOP = 10000; << 171 const size_t MAX_LOOP=10000;
154 for (std::size_t loop_counter = 0; loop_coun << 172 for (size_t loop_counter=0; loop_counter <MAX_LOOP; ++loop_counter){
155 // determine momentum/energy 173 // determine momentum/energy
156 r = G4UniformRand(); 174 r = G4UniformRand();
157 p = pmax * G4UniformRand(); << 175 p = pmax*G4UniformRand();
158 e = std::sqrt(p * p + daughtermass[0] * da << 176 e = std::sqrt(p*p + daughtermass[0]*daughtermass[0]);
159 if (r < spectrum(p, e, parentmass, daughte << 177 if (r < spectrum(p,e,parentmass,daughtermass[0]) ) break;
160 } << 178 }
161 179
162 // create daughter G4DynamicParticle << 180 //create daughter G4DynamicParticle
163 // daughter 0 (lepton) 181 // daughter 0 (lepton)
164 daughtermomentum[0] = p; 182 daughtermomentum[0] = p;
165 G4double costheta, sintheta, phi, sinphi, co << 183 G4double costheta, sintheta, phi, sinphi, cosphi;
166 costheta = 2. * G4UniformRand() - 1.0; << 184 costheta = 2.*G4UniformRand()-1.0;
167 sintheta = std::sqrt((1.0 - costheta) * (1.0 << 185 sintheta = std::sqrt((1.0-costheta)*(1.0+costheta));
168 phi = twopi * G4UniformRand() * rad; << 186 phi = twopi*G4UniformRand()*rad;
169 sinphi = std::sin(phi); 187 sinphi = std::sin(phi);
170 cosphi = std::cos(phi); 188 cosphi = std::cos(phi);
171 G4ThreeVector direction0(sintheta * cosphi, << 189 G4ThreeVector direction0(sintheta*cosphi,sintheta*sinphi,costheta);
172 auto daughterparticle = << 190 G4DynamicParticle * daughterparticle
173 new G4DynamicParticle(G4MT_daughters[0], d << 191 = new G4DynamicParticle( G4MT_daughters[0], direction0*daughtermomentum[0]);
174 products->PushProducts(daughterparticle); 192 products->PushProducts(daughterparticle);
175 193
176 // daughter 1 ,2 (nutrinos) 194 // daughter 1 ,2 (nutrinos)
177 // create neutrinos in the C.M frame of two 195 // create neutrinos in the C.M frame of two neutrinos
178 G4double energy2 = parentmass - e; << 196 G4double energy2 = parentmass-e;
179 G4double vmass = std::sqrt((energy2 - daught << 197 G4double vmass = std::sqrt((energy2-daughtermomentum[0])*(energy2+daughtermomentum[0]));
180 G4double beta = -1.0 * daughtermomentum[0] / << 198 G4double beta = -1.0*daughtermomentum[0]/energy2;
181 G4double costhetan = 2. * G4UniformRand() - << 199 G4double costhetan = 2.*G4UniformRand()-1.0;
182 G4double sinthetan = std::sqrt((1.0 - costhe << 200 G4double sinthetan = std::sqrt((1.0-costhetan)*(1.0+costhetan));
183 G4double phin = twopi * G4UniformRand() * ra << 201 G4double phin = twopi*G4UniformRand()*rad;
184 G4double sinphin = std::sin(phin); 202 G4double sinphin = std::sin(phin);
185 G4double cosphin = std::cos(phin); 203 G4double cosphin = std::cos(phin);
186 204
187 G4ThreeVector direction1(sinthetan * cosphin << 205 G4ThreeVector direction1(sinthetan*cosphin,sinthetan*sinphin,costhetan);
188 auto daughterparticle1 = new G4DynamicPartic << 206 G4DynamicParticle * daughterparticle1
189 auto daughterparticle2 = << 207 = new G4DynamicParticle( G4MT_daughters[1], direction1*(vmass/2.));
190 new G4DynamicParticle(G4MT_daughters[2], d << 208 G4DynamicParticle * daughterparticle2
>> 209 = new G4DynamicParticle( G4MT_daughters[2], direction1*(-1.0*vmass/2.));
191 210
192 // boost to the muon rest frame 211 // boost to the muon rest frame
193 G4LorentzVector p4; 212 G4LorentzVector p4;
194 p4 = daughterparticle1->Get4Momentum(); 213 p4 = daughterparticle1->Get4Momentum();
195 p4.boost(direction0.x() * beta, direction0.y << 214 p4.boost( direction0.x()*beta, direction0.y()*beta, direction0.z()*beta);
196 daughterparticle1->Set4Momentum(p4); 215 daughterparticle1->Set4Momentum(p4);
197 p4 = daughterparticle2->Get4Momentum(); 216 p4 = daughterparticle2->Get4Momentum();
198 p4.boost(direction0.x() * beta, direction0.y << 217 p4.boost( direction0.x()*beta, direction0.y()*beta, direction0.z()*beta);
199 daughterparticle2->Set4Momentum(p4); 218 daughterparticle2->Set4Momentum(p4);
200 products->PushProducts(daughterparticle1); 219 products->PushProducts(daughterparticle1);
201 products->PushProducts(daughterparticle2); 220 products->PushProducts(daughterparticle2);
202 daughtermomentum[1] = daughterparticle1->Get 221 daughtermomentum[1] = daughterparticle1->GetTotalMomentum();
203 daughtermomentum[2] = daughterparticle2->Get 222 daughtermomentum[2] = daughterparticle2->GetTotalMomentum();
204 223
205 // output message << 224
>> 225 // output message
206 #ifdef G4VERBOSE 226 #ifdef G4VERBOSE
207 if (GetVerboseLevel() > 1) { << 227 if (GetVerboseLevel()>1) {
208 G4cout << "G4TauLeptonicDecayChannel::Deca 228 G4cout << "G4TauLeptonicDecayChannel::DecayIt ";
209 G4cout << " create decay products in rest << 229 G4cout << " create decay products in rest frame " <<G4endl;
210 products->DumpInfo(); 230 products->DumpInfo();
211 } 231 }
212 #endif 232 #endif
213 return products; 233 return products;
214 } 234 }
215 235
216 G4double G4TauLeptonicDecayChannel::spectrum(G << 236
>> 237
>> 238
>> 239 G4double G4TauLeptonicDecayChannel::spectrum(G4double p,
>> 240 G4double e,
>> 241 G4double mtau,
>> 242 G4double ml)
217 { 243 {
218 G4double f1; 244 G4double f1;
219 f1 = 3.0 * e * (mtau * mtau + ml * ml) - 4.0 << 245 f1 = 3.0*e*(mtau*mtau+ml*ml)-4.0*mtau*e*e-2.0*mtau*ml*ml;
220 return p * (f1) / (mtau * mtau * mtau * mtau << 246 return p*(f1)/(mtau*mtau*mtau*mtau)/(0.6);
221 } 247 }
>> 248
>> 249
>> 250
222 251