source: trunk/source/processes/hadronic/models/chiral_inv_phase_space/cross_sections/include/G4QTauNuclearCrossSection.hh @ 1316

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27// $Id: G4QTauNuclearCrossSection.hh,v 1.1 2009/11/16 18:15:42 mkossov Exp $
28// GEANT4 tag $Name: geant4-09-03 $
29//
30//
31// GEANT4 physics class: G4QTauNuclearCrossSection -- header file
32// M.V. Kossov, CERN-ITEP(Moscow), 4-FEB-2004
33// The last update: M.V. Kossov, CERN/ITEP (Moscow) 4-Feb-04
34//
35// Short description: this G4 singletone class calculates tau-lepton-nuclear cross section
36// for the particular isotope (GetCrossSection member function)
37// ****************************************************************************************
38// ********* This HEADER is temporary moved from the photolepton_hadron directory *********
39// ******* DO NOT MAKE ANY CHANGE! With time it'll move back to photolepton...(M.K.) ******
40// ****************************************************************************************
41// Short description: reaction cross-sections for tau-nuclear reactions, which
42// are integrals over virtual equivalent photons photons. The tau-nuclear
43// reactions do not exist in GHAD, so by the present physics lists it is not
44// simulated at all.
45// --------------------------------------------------------------------------------
46
47#ifndef G4QTauNuclearCrossSection_h
48#define G4QTauNuclearCrossSection_h 1
49
50#include "G4ParticleTable.hh"
51#include "G4NucleiProperties.hh"
52#include <vector>
53#include "Randomize.hh"
54#include "G4MuonPlus.hh"
55#include "G4MuonMinus.hh"
56#include "G4VQCrossSection.hh"
57
58class G4QTauNuclearCrossSection : public G4VQCrossSection
59{
60protected:
61
62  G4QTauNuclearCrossSection()  {};
63
64public:
65
66  ~G4QTauNuclearCrossSection();
67
68  static G4VQCrossSection* GetPointer(); // Gives a pointer to this singletone
69
70  G4double ThresholdEnergy(G4int Z, G4int N, G4int PDG=15);
71
72  // At present momentum (pMom) must be in GeV (@@ Units)
73  virtual G4double GetCrossSection(G4bool fCS, G4double pMom, G4int tgZ, G4int tgN,
74                                                                             G4int pPDG=0);
75
76  G4double CalculateCrossSection(G4bool CS, G4int F, G4int I, G4int PDG, G4int Z, G4int N,
77                                                                        G4double Momentum);
78
79  G4int    GetExchangePDGCode();
80
81  G4double GetExchangeEnergy();
82
83  G4double GetVirtualFactor(G4double nu, G4double Q2);
84
85  G4double GetExchangeQ2(G4double nu);
86
87private:
88  G4int    GetFunctions(G4double a, G4double* x, G4double* y, G4double* z);
89  G4double HighEnergyJ1(G4double lE);
90  G4double HighEnergyJ2(G4double lE);
91  G4double HighEnergyJ3(G4double lE);
92  G4double SolveTheEquation(G4double f);
93  G4double Fun(G4double x);
94  G4double DFun(G4double x);
95
96// Body
97private:
98  static G4bool    onlyCS;   // flag to calculate only CS
99  static G4double  lastSig;  // Last calculated cross section
100  static G4int     lastL;    // Last used in the cross section TheLastBin
101  static G4double  lastE;    // Last used in the cross section Energy
102  static G4int     lastF;    // Last used in the cross section TheFirstBin
103  static G4double  lastG;    // Last value of gamma=lnE-ln(m)
104  static G4double  lastH;    // Last value of the High energy A-dependence
105  static G4double* lastJ1;   // Pointer to the last array of the J1 function
106  static G4double* lastJ2;   // Pointer to the last array of the J2 function
107  static G4double* lastJ3;   // Pointer to the last array of the J3 function
108  static G4int     lastPDG;  // The last projectile PDG
109  static G4int     lastN;    // The last N of calculated nucleus
110  static G4int     lastZ;    // The last Z of calculated nucleus
111  static G4double  lastP;    // Last used in the cross section Momentum
112  static G4double  lastTH;   // Last value of the Momentum Threshold
113  static G4double  lastCS;   // Last value of the Cross Section
114  static G4int     lastI;    // The last position in the DAMDB
115  static std::vector <G4double*>* J1; // Vector of pointers to the J1 tabulated functions
116  static std::vector <G4double*>* J2; // Vector of pointers to the J2 tabulated functions
117  static std::vector <G4double*>* J3; // Vector of pointers to the J3 tabulated functions
118};
119
120inline G4double G4QTauNuclearCrossSection::DFun(G4double x)// Parametrization of PhotNucCS
121{
122  static const G4double shd=1.0734;                    // HE PomShadowing(D)
123  static const G4double poc=0.0375;                    // HE Pomeron coefficient
124  static const G4double pos=16.5;                      // HE Pomeron shift
125  static const G4double reg=.11;                       // HE Reggeon slope
126  static const G4double mtu=1777.;                     // Mass of a muon in MeV
127  static const G4double lmtu=std::log(mtu);            // Log of a muon mass
128  G4double y=std::exp(x-lastG-lmtu);                   // y for the x
129  G4double flux=lastG*(2.-y*(2.-y))-1.;                // flux factor
130  return (poc*(x-pos)+shd*std::exp(-reg*x))*flux;
131}
132
133inline G4double G4QTauNuclearCrossSection::Fun(G4double x) // Integrated PhoNucCS
134{
135  G4double dlg1=lastG+lastG-1.;
136  G4double lgoe=lastG/lastE;
137  G4double HE2=HighEnergyJ2(x);
138  return dlg1*HighEnergyJ1(x)-lgoe*(HE2+HE2-HighEnergyJ3(x)/lastE);
139}
140
141inline G4double G4QTauNuclearCrossSection::HighEnergyJ1(G4double lEn)
142{
143  static const G4double le=std::log(50000.); // log(E0)
144  static const G4double le2=le*le;           // log(E0)^2
145  static const G4double a=.0375;             // a
146  static const G4double ha=a*.5;             // a/2
147  static const G4double ab=a*16.5;           // a*b
148  static const G4double d=0.11;              // d
149  static const G4double cd=1.0734/d;         // c/d
150  static const G4double ele=std::exp(-d*le); // E0^(-d)
151  return ha*(lEn*lEn-le2)-ab*(lEn-le)-cd*(std::exp(-d*lEn)-ele);
152}
153
154inline G4double G4QTauNuclearCrossSection::HighEnergyJ2(G4double lEn)
155{
156  static const G4double e=50000.;            // E0
157  static const G4double le=std::log(e);      // log(E0)
158  static const G4double le1=(le-1.)*e;       // (log(E0)-1)*E0
159  static const G4double a=.0375;             // a
160  static const G4double ab=a*16.5;           // a*b
161  static const G4double d=1.-0.11;           // 1-d
162  static const G4double cd=1.0734/d;         // c/(1-d)
163  static const G4double ele=std::exp(d*le);  // E0^(1-d)
164  G4double En=std::exp(lEn);
165  return a*((lEn-1.)*En-le1)-ab*(En-e)+cd*(std::exp(d*lEn)-ele);
166}
167
168inline G4double G4QTauNuclearCrossSection::HighEnergyJ3(G4double lEn)
169{
170  static const G4double e=50000.;            // E0
171  static const G4double le=std::log(e);      // log(E0)
172  static const G4double e2=e*e;              // E0^2
173  static const G4double leh=(le-.5)*e2;      // (log(E0)-.5)*E0^2
174  static const G4double ha=.0375*.5;         // a/2
175  static const G4double hab=ha*16.5;         // a*b/2
176  static const G4double d=2.-.11;            // 2-d
177  static const G4double cd=1.0734/d;         // c/(2-d)
178  static const G4double ele=std::exp(d*le);  // E0^(2-d)
179  G4double lastE2=std::exp(lEn+lEn);
180  return ha*((lEn-.5)*lastE2-leh)-hab*(lastE2-e2)+cd*(std::exp(d*lEn)-ele);
181}
182
183#endif
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