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26
27
28 #include "G4NeutrinoElectronNcXsc.hh"
29 #include "G4PhysicalConstants.hh"
30 #include "G4SystemOfUnits.hh"
31 #include "G4DynamicParticle.hh"
32 #include "G4ParticleTable.hh"
33 #include "G4IonTable.hh"
34 #include "G4HadTmpUtil.hh"
35 #include "G4Proton.hh"
36 #include "G4NistManager.hh"
37
38 using namespace std;
39 using namespace CLHEP;
40
41 G4NeutrinoElectronNcXsc::G4NeutrinoElectronNcXsc()
42 : G4VCrossSectionDataSet("NuElectronNcXsc")
43 {
44 // PDG2016: Gf=1.1663787(6)e-5*(hc)^3/GeV^2
45 // fCofXsc = Gf*Gf*MeC2*2/pi
46
47 fCofXsc = 1.36044e-22;
48 fCofXsc *= hbarc*hbarc*electron_mass_c2;
49 fCofXsc /= halfpi;
50
51 // G4cout<<"hbarc = "<<hbarc/MeV/fermi<<" MeV*fermi"<<G4endl;
52
53 // PDG2016: sin^2 theta Weinberg
54
55 fSin2tW = 0.23129; // 0.2312;
56
57 fCutEnergy = 0.; // default value
58 fBiasingFactor = 1.;
59 }
60
61 G4NeutrinoElectronNcXsc::~G4NeutrinoElectronNcXsc()
62 {}
63
64 //////////////////////////////////////////////////////
65
66 G4bool
67 G4NeutrinoElectronNcXsc::IsElementApplicable( const G4DynamicParticle* aPart, G4int, const G4Material*)
68 {
69 G4bool result = false;
70 G4String pName = aPart->GetDefinition()->GetParticleName();
71 G4double minEnergy = 0., energy = aPart->GetTotalEnergy();
72 // Z *= 1;
73 if( fCutEnergy > 0. ) // min detected recoil electron energy
74 {
75 minEnergy = 0.5*(fCutEnergy+sqrt(fCutEnergy*(fCutEnergy+2.*electron_mass_c2)));
76 }
77 if( ( pName == "nu_e" || pName == "anti_nu_e" ||
78 pName == "nu_mu" || pName == "anti_nu_mu" ||
79 pName == "nu_tau" || pName == "anti_nu_tau" ) &&
80 energy > minEnergy )
81 {
82 result = true;
83 }
84 return result;
85 }
86
87 ////////////////////////////////////////////////////
88
89 G4double G4NeutrinoElectronNcXsc::
90 GetElementCrossSection(const G4DynamicParticle* aPart, G4int ZZ,
91 const G4Material*)
92 {
93 G4double result = 0., cofL, cofR, cofL2, cofR2, cofLR;
94
95 G4double energy = aPart->GetTotalEnergy();
96 G4String pName = aPart->GetDefinition()->GetParticleName();
97
98 if( pName == "nu_e")
99 {
100 cofL = 0.5 + fSin2tW;
101 cofR = fSin2tW;
102 }
103 else if( pName == "anti_nu_e")
104 {
105 cofL = fSin2tW;
106 cofR = 0.5 + fSin2tW;
107 }
108 else if( pName == "nu_mu")
109 {
110 cofL = -0.5 + fSin2tW;
111 cofR = fSin2tW;
112 }
113 else if( pName == "anti_nu_mu")
114 {
115 cofL = fSin2tW;
116 cofR = -0.5 + fSin2tW;
117 }
118 else if( pName == "nu_tau") // vmg: nu_tau as nu_mu ???
119 {
120 cofL = -0.5 + fSin2tW;
121 cofR = fSin2tW;
122 }
123 else if( pName == "anti_nu_tau")
124 {
125 cofL = fSin2tW;
126 cofR = -0.5 + fSin2tW;
127 }
128 else
129 {
130 return result;
131 }
132 // if( energy <= electron_mass_c2 ) return result;
133
134 cofL2 = cofL*cofL;
135 cofR2 = cofR*cofR;
136 cofLR = cofL*cofR;
137
138 if( fCutEnergy > 0. )
139 {
140 G4double tM = 2.*energy*energy/(electron_mass_c2 + 2.*energy);
141 G4double tM2 = tM*tM;
142 G4double tM3 = tM*tM2;
143 G4double tC = fCutEnergy;
144 G4double tC2 = tC*tC;
145 G4double tC3 = tC*tC2;
146
147 result = (cofL2+cofR2)*(tM-tC);
148 result -= (cofR2+cofLR*0.5*electron_mass_c2/energy)*(tM2-tC2)/energy;
149 result += cofR2*(tM3-tC3)/energy/energy/3.;
150 }
151 else
152 {
153 G4double rtM = 2.*energy/(electron_mass_c2 + 2.*energy);
154 G4double rtM2 = rtM*rtM;
155 G4double rtM3 = rtM*rtM2;
156
157 result = (cofL2+cofR2)*rtM*energy;
158 result -= (cofR2*energy+cofLR*0.5*electron_mass_c2)*rtM2;
159 result += cofR2*rtM3*energy/3.;
160 }
161 // result = cofL*cofL + cofR*cofR/3.;
162 // G4cout<<"cofL2 + cofR2/3. = "<<result<<G4endl;
163 // result -= 0.5*cofL*cofR*electron_mass_c2/energy;
164
165 G4double aa = 1.;
166 G4double bb = 1.7;
167 G4double gw = 2.141*GeV;
168 G4double dd = 5000.;
169 G4double mw = 80.385*GeV;
170 G4double mz = 91.1876*GeV;
171
172 G4double emass = electron_mass_c2;
173 G4double totS = 2.*energy*emass + emass*emass;
174
175 if( energy > 50.*GeV )
176 {
177 result *= bb;
178 result /= 1.+ aa*totS/mz/mz;
179
180 if( pName == "anti_nu_e")
181 {
182 result *= 1. + dd*gw*gw*totS/( (totS-mw*mw)*(totS-mw*mw)+gw*gw*mw*mw );
183 }
184 }
185
186 result *= fCofXsc; //*energy;
187
188 result *= ZZ; // incoherent sum over all element electrons
189
190 result *= fBiasingFactor;
191
192 return result;
193 }
194
195