| Geant4 Cross Reference |
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25 //
26
27
28 #include "G4NeutrinoElectronCcXsc.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 "G4NistManager.hh"
36
37 #include "G4MuonMinus.hh"
38 #include "G4TauMinus.hh"
39
40 using namespace std;
41 using namespace CLHEP;
42
43 G4NeutrinoElectronCcXsc::G4NeutrinoElectronCcXsc()
44 : G4VCrossSectionDataSet("NuElectronCcXsc")
45 {
46 // PDG2016: Gf=1.1663787(6)e-5*(hc)^3/GeV^2
47 // fCofXsc = Gf*Gf*MeC2*2/pi
48
49 fCofXsc = 1.36044e-22;
50 fCofXsc *= hbarc*hbarc*electron_mass_c2;
51 fCofXsc /= halfpi;
52
53 // G4cout<<"fCofXsc = "<<fCofXsc*GeV/cm2<<" cm2/GeV"<<G4endl;
54
55 // G4cout<<"hbarc = "<<hbarc/MeV/fermi<<" MeV*fermi"<<G4endl;
56
57 // PDG2016: sin^2 theta Weinberg
58
59 fSin2tW = 0.23129; // 0.2312;
60
61 fCutEnergy = 0.; // default value
62
63 fBiasingFactor = 1.; // default as physics
64
65 theMuonMinus = G4MuonMinus::MuonMinus();
66 theTauMinus = G4TauMinus::TauMinus();
67 }
68
69 G4NeutrinoElectronCcXsc::~G4NeutrinoElectronCcXsc()
70 {}
71
72 //////////////////////////////////////////////////////
73
74 G4bool
75 G4NeutrinoElectronCcXsc::IsElementApplicable( const G4DynamicParticle* aPart, G4int, const G4Material*)
76 {
77 G4bool result = false;
78 G4String pName = aPart->GetDefinition()->GetParticleName();
79 G4double minEnergy = 0., energy = aPart->GetTotalEnergy();
80 G4double fmass, emass = electron_mass_c2;
81
82 if( pName == "anti_nu_e" || pName == "nu_mu" || pName == "anti_nu_mu" ) fmass = theMuonMinus->GetPDGMass();
83 else if( pName == "nu_tau" || pName == "anti_nu_tau" ) fmass = theTauMinus->GetPDGMass();
84 else fmass = emass;
85
86 minEnergy = (fmass-emass)*(fmass+emass)/emass;
87
88 if( ( pName == "nu_mu" || pName == "anti_nu_mu" ||
89 pName == "nu_tau" || pName == "anti_nu_tau" ) &&
90 energy > minEnergy )
91 {
92 result = true;
93 }
94 return result;
95 }
96
97 ////////////////////////////////////////////////////
98
99 G4double G4NeutrinoElectronCcXsc::
100 GetElementCrossSection(const G4DynamicParticle* aPart, G4int ZZ,
101 const G4Material*)
102 {
103 G4double result = 0., totS, fmass, fmass2, emass=electron_mass_c2, emass2;
104
105 G4double energy = aPart->GetTotalEnergy();
106 G4String pName = aPart->GetDefinition()->GetParticleName();
107
108 emass2 = emass*emass;
109 totS = 2.*energy*emass + emass2;
110
111 if( pName == "anti_nu_e" || pName == "nu_mu")
112 {
113 fmass = theMuonMinus->GetPDGMass();
114 fmass2 = fmass*fmass;
115 result = (1. - fmass2/totS)*(1. - fmass2/totS);
116 }
117 else if( pName == "anti_nu_mu")
118 {
119 fmass = theMuonMinus->GetPDGMass();
120 fmass2 = fmass*fmass;
121
122 result = (1.+ emass2/totS)*(1.+ fmass2/totS);
123 result += (1.- emass2/totS)*(1.- fmass2/totS)/3.;
124 result *= 0.25*(1. - fmass2/totS)*(1. - fmass2/totS);
125 }
126 else if( pName == "nu_tau")
127 {
128 fmass = theTauMinus->GetPDGMass();
129 fmass2 = fmass*fmass;
130 result = (1. - fmass2/totS)*(1. - fmass2/totS);
131 }
132 else if( pName == "anti_nu_tau")
133 {
134 fmass = theTauMinus->GetPDGMass();
135 fmass2 = fmass*fmass;
136
137 result = (1.+ emass2/totS)*(1.+ fmass2/totS);
138 result += (1.- emass2/totS)*(1.- fmass2/totS)/3.;
139 result *= 0.25*(1. - fmass2/totS)*(1. - fmass2/totS);
140 }
141 else
142 {
143 return result;
144 }
145 // if( energy <= electron_mass_c2 ) return result;
146
147 G4double aa = 1.;
148 G4double bb = 1.7;
149 G4double gw = 2.141*GeV;
150 G4double dd = 5000.;
151 G4double mw = 80.385*GeV;
152
153 if( energy > 50.*GeV )
154 {
155 result *= bb;
156 result /= 1.+ aa*totS/mw/mw;
157
158 if( pName == "anti_nu_e")
159 {
160 result *= 1. + dd*gw*gw*totS/( (totS-mw*mw)*(totS-mw*mw)+gw*gw*mw*mw );
161 }
162 }
163 result *= fCofXsc; //*energy;
164 result *= energy + 0.5*emass;
165 result *= ZZ; // incoherent sum over all element electrons
166
167 result *= fBiasingFactor; // biasing up, if set >1
168
169 return result;
170 }
171
172