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G4QMuonNuclearCrossSection.hh
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30 // GEANT4 physics class: G4QMuonNuclearCrossSection -- header file
31 // M.V. Kossov, CERN-ITEP(Moscow), 4-FEB-2004
32 // The last update: M.V. Kossov, CERN/ITEP (Moscow) 4-Feb-04
33 //
34 // Short description: this G4 singletone class calculates muonNuclear cross section for
35 // the particular isotope (GetCrossSection member function)
36 // ****************************************************************************************
37 // ********* This HEADER is temporary moved from the photolepton_hadron directory *********
38 // ******* DO NOT MAKE ANY CHANGE! With time it'll move back to photolepton...(M.K.) ******
39 // ****************************************************************************************
40 // Short description: reaction cross-sections for muon-nuclear reactions, which
41 // are integrals over virtual equivalent photons photons. The muon-nuclear GHAD
42 // model (not CHIPS) gives 2-3 times smaller scattering angle and deposited energy.
43 // --------------------------------------------------------------------------------
44 
45 #ifndef G4QMuonNuclearCrossSection_h
46 #define G4QMuonNuclearCrossSection_h 1
47 
48 #include "G4ParticleTable.hh"
49 #include "G4NucleiProperties.hh"
50 #include <vector>
51 #include "Randomize.hh"
52 #include "G4MuonPlus.hh"
53 #include "G4MuonMinus.hh"
54 #include "G4VQCrossSection.hh"
55 
56 class G4QMuonNuclearCrossSection : public G4VQCrossSection
57 {
58 protected:
59 
60  G4QMuonNuclearCrossSection() {};
61 
62 public:
63 
64  ~G4QMuonNuclearCrossSection();
65 
66  static G4VQCrossSection* GetPointer(); // Gives a pointer to this singletone
67 
68  G4double ThresholdEnergy(G4int Z, G4int N, G4int PDG=13);
69 
70  // At present momentum (pMom) must be in GeV (@@ Units)
71  virtual G4double GetCrossSection(G4bool fCS, G4double pMom, G4int tgZ, G4int tgN,
72  G4int pPDG=0);
73 
74  G4double CalculateCrossSection(G4bool CS, G4int F, G4int I, G4int PDG, G4int Z, G4int N,
75  G4double Momentum);
76 
77  G4int GetExchangePDGCode();
78 
79  G4double GetExchangeEnergy();
80 
81  G4double GetVirtualFactor(G4double nu, G4double Q2);
82 
83  G4double GetExchangeQ2(G4double nu);
84 
85 private:
86  G4int GetFunctions(G4double a, G4double* x, G4double* y, G4double* z);
87  G4double HighEnergyJ1(G4double lE);
88  G4double HighEnergyJ2(G4double lE);
89  G4double HighEnergyJ3(G4double lE);
90  G4double SolveTheEquation(G4double f);
91  G4double Fun(G4double x);
92  G4double DFun(G4double x);
93 
94 // Body
95 private:
96  static G4bool onlyCS; // flag to calculate only CS
97  static G4double lastSig; // Last calculated cross section
98  static G4int lastL; // Last used in the cross section TheLastBin
99  static G4double lastE; // Last used in the cross section Energy
100  static G4int lastF; // Last used in the cross section TheFirstBin
101  static G4double lastG; // Last value of gamma=lnE-ln(m)
102  static G4double lastH; // Last value of the High energy A-dependence
103  static G4double* lastJ1; // Pointer to the last array of the J1 function
104  static G4double* lastJ2; // Pointer to the last array of the J2 function
105  static G4double* lastJ3; // Pointer to the last array of the J3 function
106  static G4int lastPDG; // The last projectile PDG
107  static G4int lastN; // The last N of calculated nucleus
108  static G4int lastZ; // The last Z of calculated nucleus
109  static G4double lastP; // Last used in the cross section Momentum
110  static G4double lastTH; // Last value of the Momentum Threshold
111  static G4double lastCS; // Last value of the Cross Section
112  static G4int lastI; // The last position in the DAMDB
113  static std::vector <G4double*>* J1; // Vector of pointers to the J1 tabulated functions
114  static std::vector <G4double*>* J2; // Vector of pointers to the J2 tabulated functions
115  static std::vector <G4double*>* J3; // Vector of pointers to the J3 tabulated functions
116 };
117 
118 inline G4double G4QMuonNuclearCrossSection::DFun(G4double x)// Parametrization of PhotNucCS
119 {
120  static const G4double shd=1.0734; // HE PomShadowing(D)
121  static const G4double poc=0.0375; // HE Pomeron coefficient
122  static const G4double pos=16.5; // HE Pomeron shift
123  static const G4double reg=.11; // HE Reggeon slope
124  static const G4double mmu=105.65839; // Mass of a muon in MeV
125  static const G4double lmmu=std::log(mmu); // Log of a muon mass
126  G4double y=std::exp(x-lastG-lmmu); // y for the x
127  G4double flux=lastG*(2.-y*(2.-y))-1.; // flux factor
128  return (poc*(x-pos)+shd*std::exp(-reg*x))*flux;
129 }
130 
131 inline G4double G4QMuonNuclearCrossSection::Fun(G4double x) // Integrated PhoNucCS
132 {
133  G4double dlg1=lastG+lastG-1.;
134  G4double lgoe=lastG/lastE;
135  G4double HE2=HighEnergyJ2(x);
136  return dlg1*HighEnergyJ1(x)-lgoe*(HE2+HE2-HighEnergyJ3(x)/lastE);
137 }
138 
139 inline G4double G4QMuonNuclearCrossSection::HighEnergyJ1(G4double lEn)
140 {
141  static const G4double le=std::log(50000.); // log(E0)
142  static const G4double le2=le*le; // log(E0)^2
143  static const G4double a=.0375; // a
144  static const G4double ha=a*.5; // a/2
145  static const G4double ab=a*16.5; // a*b
146  static const G4double d=0.11; // d
147  static const G4double cd=1.0734/d; // c/d
148  static const G4double ele=std::exp(-d*le); // E0^(-d)
149  return ha*(lEn*lEn-le2)-ab*(lEn-le)-cd*(std::exp(-d*lEn)-ele);
150 }
151 
152 inline G4double G4QMuonNuclearCrossSection::HighEnergyJ2(G4double lEn)
153 {
154  static const G4double e=50000.; // E0
155  static const G4double le=std::log(e); // log(E0)
156  static const G4double le1=(le-1.)*e; // (log(E0)-1)*E0
157  static const G4double a=.0375; // a
158  static const G4double ab=a*16.5; // a*b
159  static const G4double d=1.-0.11; // 1-d
160  static const G4double cd=1.0734/d; // c/(1-d)
161  static const G4double ele=std::exp(d*le); // E0^(1-d)
162  G4double En=std::exp(lEn);
163  return a*((lEn-1.)*En-le1)-ab*(En-e)+cd*(std::exp(d*lEn)-ele);
164 }
165 
166 inline G4double G4QMuonNuclearCrossSection::HighEnergyJ3(G4double lEn)
167 {
168  static const G4double e=50000.; // E0
169  static const G4double le=std::log(e); // log(E0)
170  static const G4double e2=e*e; // E0^2
171  static const G4double leh=(le-.5)*e2; // (log(E0)-.5)*E0^2
172  static const G4double ha=.0375*.5; // a/2
173  static const G4double hab=ha*16.5; // a*b/2
174  static const G4double d=2.-.11; // 2-d
175  static const G4double cd=1.0734/d; // c/(2-d)
176  static const G4double ele=std::exp(d*le); // E0^(2-d)
177  G4double lastE2=std::exp(lEn+lEn);
178  return ha*((lEn-.5)*lastE2-leh)-hab*(lastE2-e2)+cd*(std::exp(d*lEn)-ele);
179 }
180 
181 #endif
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