| 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 7 | // * conditions of the Geant4 Software License, included in the file * |
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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| 9 | // * include a list of copyright holders. * |
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| 10 | // * * |
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| 11 | // * Neither the authors of this software system, nor their employing * |
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| 12 | // * institutes,nor the agencies providing financial support for this * |
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| 13 | // * work make any representation or warranty, express or implied, * |
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| 14 | // * regarding this software system or assume any liability for its * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 16 | // * for the full disclaimer and the limitation of liability. * |
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| 17 | // * * |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 19 | // * technical work of the GEANT4 collaboration. * |
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| 20 | // * By using, copying, modifying or distributing the software (or * |
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| 21 | // * any work based on the software) you agree to acknowledge its * |
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| 22 | // * use in resulting scientific publications, and indicate your * |
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| 23 | // * acceptance of all terms of the Geant4 Software license. * |
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| 24 | // ******************************************************************** |
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| 25 | // |
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| 26 | // |
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| 27 | // G4 Tools program: NuMu DIS (x,Q2) approximation is integrated over x |
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| 28 | // ..................................................... |
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| 29 | // Created: M.V. Kossov, CERN/ITEP(Moscow), 30-Sept-05 |
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| 30 | // |
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| 31 | //===================================================================== |
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| 32 | #include "globals.hh" |
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| 33 | #include <iostream> |
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| 34 | #include <fstream> |
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| 35 | #include <vector> |
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| 36 | #include "G4ios.hh" |
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| 37 | #include <CLHEP/GenericFunctions/LogGamma.hh> |
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| 38 | |
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| 39 | void strucf(int A, double x, double ydME, double& f2, double& xf3, double& fL) |
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| 40 | { |
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| 41 | const Genfun::LogGamma lGam; |
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| 42 | double N=3., D=0., Del=0., U2=0., U3=0., V=0.; |
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| 43 | double Q2=x*ydME; |
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| 44 | double r=0.; |
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| 45 | double max=1.; |
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| 46 | double H=1.22; |
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| 47 | if(A==1) // Proton |
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| 48 | { |
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| 49 | r=std::sqrt(Q2/1.66); |
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| 50 | max=.5; |
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| 51 | } |
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| 52 | else if(A<13) // Light nuclei |
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| 53 | { |
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| 54 | double f=Q2/4.62; |
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| 55 | r=f*f; |
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| 56 | max=.3; |
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| 57 | if(A>2) H=1.; |
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| 58 | } |
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| 59 | else if(A>0) // Heavy nuclei |
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| 60 | { |
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| 61 | double f=Q2/3.4; |
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| 62 | double ff=f*f; |
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| 63 | r=ff*ff; |
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| 64 | max=.5; |
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| 65 | H=1.; |
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| 66 | } |
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| 67 | else G4cout<<"strucf: A="<<A<<" <= 0"<< G4endl; |
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| 68 | // |
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| 69 | N=3.+.3581*std::log(1.+Q2/.04); // a#of partons in the nonperturbative phase space |
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| 70 | Del=(1.+r)/(12.5+r/max); |
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| 71 | double S=std::pow(1.+.6/Q2,-1.-Del); |
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| 72 | D=H*S*(1.-.5*S); |
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| 73 | V=3*(1.-D)*(N-1.); |
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| 74 | double cc=Q2/.08; |
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| 75 | double cc2=cc*cc; |
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| 76 | double C=(1.+cc2)/(1.+cc2/.24)/(1.+Q2/21.6); |
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| 77 | double c3=C+C+C; |
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| 78 | double uu=std::exp(lGam(N-Del)-lGam(N-1.)-lGam(1.-Del))/N; |
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| 79 | U2=(c3+N-3.)*uu; |
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| 80 | U3=c3*uu; |
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| 81 | // From here the Q2 coefficients are used |
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| 82 | double x1=std::pow(1.-x,N-2.); |
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| 83 | double pp=D*std::pow(x,-Del)*x1; |
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| 84 | double dir=V*x*x1; |
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| 85 | double per=U2*pp; |
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| 86 | f2 = per + dir; |
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| 87 | xf3= U3*pp+dir; |
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| 88 | fL = per/4.; |
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| 89 | return; |
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| 90 | } |
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| 91 | |
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| 92 | void getFun(int A, double lx, double ydME, double* f) |
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| 93 | { |
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| 94 | double f2=0., xf3=0., fL=0.; |
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| 95 | if (lx>0.5) G4cerr<<"***getFun: ln(x)="<<lx<<">.5"<<G4endl; |
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| 96 | double x=std::exp(lx); |
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| 97 | strucf(A, x, ydME, f2, xf3, fL); |
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| 98 | f[0]=x*f2; // direct part |
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| 99 | f[1]=x*(-f2+xf3); // *y (neutrino) part |
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| 100 | f[2]=x*(-f2-xf3); // *y (anti-neutrino) part |
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| 101 | f[3]=x*(f2-fL-xf3); // *y2 (neutrino) part |
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| 102 | f[4]=x*(f2-fL+xf3); // *y2 (anti-neutrino) part |
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| 103 | } |
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| 104 | |
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| 105 | int main() |
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| 106 | { |
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| 107 | const double reps=.01; // relative accuracy of the total Q2 integral calculation |
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| 108 | const double xeps=.0001; // relative accuracy of the total X integral calculation |
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| 109 | // ========= |
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| 110 | const double GF=1.16637e-5; // Fermi constant in GeV^-2 |
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| 111 | const double GF2=GF*GF; // Squared Fermi constant in GeV^-4 |
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| 112 | const double MW=80.425; // Mass of W-boson in GeV |
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| 113 | const double MW2=MW*MW; // Squared mass of W-boson in GeV^2 |
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| 114 | const double MW4=MW2*MW2; // Quadro mass of W-boson in GeV^4 |
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| 115 | const double hc2=38937932300.;// (hc)^2 in GeV^2*10^-38cm2 to convert GeV^-2 to 10^-38cm2 |
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| 116 | const double pif=3.14159265*4;// 4pi |
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| 117 | const double sik=GF2*MW4*hc2/pif; // precalculated coefficient |
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| 118 | const double mpi=.1349766; // pi0 meson mass in GeV |
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| 119 | const double mpi2=mpi*mpi; // m_pi^2 in GeV^2 |
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| 120 | const double me=.00051099892; // electron mass in GeV |
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| 121 | const double me2=me*me; // m_e^2 in GeV^2 |
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| 122 | const double hme2=me2/2; // .5*m_e^2 in GeV^2 |
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| 123 | const double mmu=.105658369; // mu meson mass in GeV |
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| 124 | const double mmu2=mmu*mmu; // m_mu^2 in GeV^2 |
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| 125 | const double hmmu2=mmu2/2; // .5*m_mu^2 in GeV^2 |
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| 126 | const double mtau=1.777; // tau meson mass in GeV |
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| 127 | const double mtau2=mtau*mtau; // m_tau^2 in GeV^2 |
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| 128 | const double hmtau2=mtau2/2; // .5*m_e^2 in GeV^2 |
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| 129 | const double mp=.93827203; // proton mass in GeV |
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| 130 | const double mn=.93956536; // neutron mass in GeV |
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| 131 | const double md=1.87561282; // deuteron mass in GeV |
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| 132 | const double MN=.931494043; // Nucleon mass (inside nucleus) in GeV (atomic mass unit) |
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| 133 | const double mp2=mp*mp; // m_p^2 in GeV^2 |
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| 134 | const double MN2=MN*MN; // M_N^2 in GeV^2 |
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| 135 | const double dMN=MN+MN; // 2*M_N in GeV |
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| 136 | const double EminE=me+me2/dMN;// Threshold for muon production |
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| 137 | const double EminMu=mmu+mmu2/dMN; // Threshold for muon production |
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| 138 | const double EminTau=mmu+mmu2/dMN; // Threshold for muon production |
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| 139 | //std::ofstream fileNuMuX("NuMuXQ2.out", std::ios::out); |
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| 140 | //fileNuMuX.setf( std::ios::scientific, std::ios::floatfield ); |
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| 141 | // _____ Begin of Test Area |
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| 142 | //Genfun::LogGamma logGamma; |
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| 143 | //double n=4.9; |
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| 144 | //double g=exp(logGamma(n)); |
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| 145 | //G4cout<<"Gamma("<<n<<") = "<<g<<G4endl; |
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| 146 | // ^^^^^ End of Test Area |
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| 147 | // |
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| 148 | double f[5]; // A working array |
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| 149 | int A=12; // Neucleus for which calculations should be done |
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| 150 | double lEnuMin=std::log(EminMu); // Log of Minimum energy of neutrino |
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| 151 | double lEnuMax=std::log(300.); // Log of Maximum energy of neutrino |
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| 152 | int nE=20; |
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| 153 | double dlE=(lEnuMax-lEnuMin)/nE; |
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| 154 | G4cout<<"Emin="<<EminMu<<",lEi="<<lEnuMin<<",lEa="<<lEnuMax<<",dlE="<<dlE<<G4endl; |
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| 155 | for(double lEnu=lEnuMin+dlE/2; lEnu<lEnuMax; lEnu+=dlE) |
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| 156 | { |
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| 157 | double Enu=std::exp(lEnu); // Energy of neutrino/anti-neutrino |
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| 158 | double dEnu=Enu+Enu; // doubled energy of nu/anu |
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| 159 | double Enu2=Enu*Enu; // squared energy of nu/anu |
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| 160 | double ME=Enu*MN; // M*E |
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| 161 | double dME=ME+ME; // 2*M*E |
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| 162 | double DIStsig=1.; // Total curent DIS cross-section to be integrated |
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| 163 | double DISmsig=1.e20; // Total remembered DIS cross-section |
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| 164 | double dEMN=(dEnu+MN)*ME; |
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| 165 | double MEm=ME-hmmu2; |
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| 166 | double sqE=Enu*std::sqrt(MEm*MEm-mmu2*MN2); |
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| 167 | double E2M=MN*Enu2-(Enu+MN)*hmmu2; |
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| 168 | double ymax=(E2M+sqE)/dEMN; |
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| 169 | double ymin=(E2M-sqE)/dEMN; |
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| 170 | // The Q2min/max calculation is not necessary in this method |
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| 171 | //double rmin=1.-ymin; |
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| 172 | //double rhm2E=hmmu2/Enu2; |
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| 173 | //double Q2min=(Enu2+Enu2)*(rmin-rhm2E-sqrt(rmin*rmin-rhm2E-rhm2E)); |
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| 174 | //double Q2max=dME*ymax; |
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| 175 | int nY=8; |
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| 176 | //G4cout<<"*** E="<<Enu<<", N="<<nY<<", yi="<<ymin<<" < ya="<<ymax<<G4endl; |
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| 177 | while(std::fabs(DIStsig-DISmsig)/DIStsig>reps) |
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| 178 | { |
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| 179 | DISmsig=DIStsig; |
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| 180 | DIStsig=0.; |
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| 181 | nY*=2; |
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| 182 | double dY=(ymax-ymin)/nY; |
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| 183 | for(double y=ymin+dY/2; y<ymax; y+=dY) |
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| 184 | { |
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| 185 | double y2=y*y; |
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| 186 | double DISxint=1.; // Curent DIS x-integral |
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| 187 | double DISmint=1.e20; // Remembered DIS x-integral |
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| 188 | double lXmin=std::log((std::sqrt(Enu2+mmu2)-Enu)/MN); |
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| 189 | double lXmax=0.; // Temporary, while QES is in DIS |
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| 190 | double ydME=y*dME; |
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| 191 | int nX=8; |
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| 192 | while(std::fabs(DISxint-DISmint)/DISxint>xeps) |
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| 193 | { |
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| 194 | DISmint=DISxint; |
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| 195 | DISxint=0.; |
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| 196 | nX*=2; |
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| 197 | double dlX=(lXmax-lXmin)/nX; |
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| 198 | for(double lX=lXmin+dlX/2; lX<lXmax; lX+=dlX) |
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| 199 | { |
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| 200 | getFun(A, lX, ydME, f); |
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| 201 | double dik=std::exp(lX)*ydME+MW2; |
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| 202 | //DISxint+=(f[0]+f[0]+(y+y)*f[1]+y2*f[3])/dik/dik; // neutrino |
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| 203 | DISxint+=(f[0]+f[0]+(y+y)*f[2]+y2*f[4])/dik/dik; // anti-neutrino |
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| 204 | //G4cout<<f[0]<<","<<f[1]<<","<<f[2]<<","<<f[3]<<","<<f[4]<<G4endl; |
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| 205 | } |
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| 206 | DISxint*=dlX; |
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| 207 | //G4cout<<"--- E="<<Enu<<" --- Q2="<<Q2<<" --- nX="<<nX<<", iX="<<DISxint |
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| 208 | // <<", mX="<<DISmint<<", rX="<<(DISxint-DISmint)/DISxint<<G4endl; |
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| 209 | } |
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| 210 | //G4cout<<"(E="<<Enu<<"), Q2="<<Q2<<", I="<<DISxint/dik/dik<<G4endl; |
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| 211 | DIStsig+=DISxint; |
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| 212 | } |
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| 213 | DIStsig*=dY; |
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| 214 | //G4cout<<"=== E="<<Enu<<" ===> nQ="<<nQ2<<", iQ="<<DIStsig<<", mQ="<<DISmsig |
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| 215 | // <<", rQ="<<(DIStsig-DISmsig)/DIStsig<<G4endl; |
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| 216 | } |
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| 217 | DIStsig*=sik*dMN; // Jakobian is 2ME => instead of 1/E must be *2M |
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| 218 | G4cout<<"*** E="<<Enu<<",sig/E="<<DIStsig<<G4endl; |
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| 219 | } // End of the Enery LOOP |
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| 220 | // int np=0; |
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| 221 | //for(int m=0; m<2; m++) |
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| 222 | //{ |
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| 223 | // //fileNuMuX<<" static const G4double SH"<<n<<"[nH]={"<<G4endl<<" "; |
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| 224 | // //G4cout<<"**** A_high="<<m<<G4endl; |
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| 225 | // np=0; |
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| 226 | // int nC=14; |
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| 227 | // for(G4int en=0; en<nC; en++) |
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| 228 | // { |
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| 229 | // //G4double sig=1.; |
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| 230 | // np++; |
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| 231 | // //if(np==7) // Write by 7 number in brackets |
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| 232 | // //{ |
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| 233 | // // if(en==nC-1) fileNuMuX<<sig<<"};"<<G4endl; |
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| 234 | // // else fileNuMuX<<sig<<","<<G4endl<<" "; |
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| 235 | // //} |
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| 236 | // //else fileNuMuX<<sig<<","; |
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| 237 | // //if(np==7) np=0; |
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| 238 | // } // End of the point LOOP |
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| 239 | //} // End of the isotop LOOP |
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| 240 | return EXIT_SUCCESS; |
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| 241 | } |
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