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