| 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: NuE 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 Q2, double& f2, double& xf3, double& fL) |
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| 40 | { |
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| 41 | //const double MN=.931494043; // Nucleon mass (inside nucleus, atomic mass unit, GeV) |
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| 42 | //const double MN2=MN*MN; // M_N^2 in GeV^2 |
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| 43 | //const double mpi=.13957018; // charged pi meson mass in GeV |
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| 44 | //const double Wt=MN+mpi; // Delta threshold |
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| 45 | //const double W2t=Wt*Wt; // Squared Delta threshold |
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| 46 | const Genfun::LogGamma lGam; |
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| 47 | static int mA=0; |
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| 48 | static double mQ2=0., mN, mD, mDel, mU2, mU3, mV; |
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| 49 | //static double mUU; |
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| 50 | double N=3., D=0., Del=0., U2=0., U3=0., V=0.; |
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| 51 | //double UU=0.; |
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| 52 | if(A==mA && Q2==mQ2) // Associative memory for acceleration |
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| 53 | { |
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| 54 | N =mN; |
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| 55 | D =mD; |
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| 56 | Del=mDel; |
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| 57 | U2 =mU2; |
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| 58 | U3 =mU3; |
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| 59 | //UU =mUU; |
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| 60 | V =mV; |
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| 61 | } |
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| 62 | else |
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| 63 | { |
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| 64 | //double r=0.; |
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| 65 | double min=.077; // Delta(0) |
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| 66 | double max=.47; // Hard Pomeron |
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| 67 | //double H=1.22; |
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| 68 | if(Q2<=0.) G4cout<<"strucf: Q2="<<Q2<<" <= 0"<< G4endl; |
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| 69 | double Q=std::sqrt(Q2); |
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| 70 | //if(A==1) // Proton |
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| 71 | //{ |
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| 72 | // r=std::sqrt(Q2/1.66); |
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| 73 | // max=.5; |
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| 74 | //} |
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| 75 | //else if(A<13) // Light nuclei |
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| 76 | //{ |
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| 77 | // double f=Q2/4.62; |
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| 78 | // r=f*f; |
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| 79 | // max=.3; |
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| 80 | // if(A>2) H=1.; |
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| 81 | //} |
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| 82 | //else if(A>0) // Heavy nuclei |
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| 83 | //{ |
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| 84 | // double f=Q2/3.4; |
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| 85 | // double ff=f*f; |
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| 86 | // r=ff*ff; |
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| 87 | // max=.5; |
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| 88 | // H=1.; |
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| 89 | //} |
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| 90 | //else G4cout<<"strucf: A="<<A<<" <= 0"<< G4endl; |
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| 91 | // |
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| 92 | N=3.+.3581*std::log(1.+Q2/.04); // a#of partons in the nonperturbative phase space |
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| 93 | Del=min+(max-min)/(1.+5./Q); |
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| 94 | D=0.68*std::pow(1.+.145/Q2,-1.-Del); // 0.68=1-0.34, m2=.145 GeV2 |
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| 95 | V=3*(1.-D)*(N-1.); |
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| 96 | double c3=.75; // 3*0.25 |
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| 97 | double uu=std::exp(lGam(N-Del)-lGam(N-1.)-lGam(1.-Del))/N; |
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| 98 | U2=(c3+N-3.)*uu; |
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| 99 | U3=c3*uu; |
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| 100 | mA = A; |
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| 101 | mQ2 = Q2; |
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| 102 | mN = N; |
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| 103 | mD = D; |
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| 104 | mDel=Del; |
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| 105 | mU2 =U2; |
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| 106 | mU3 =U3; |
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| 107 | //mUU =UU; // @@ |
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| 108 | mV =V; |
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| 109 | } |
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| 110 | // From here the Q2 coefficients are used |
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| 111 | double x1=std::pow(1.-x,N-2.); |
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| 112 | double pp=D*std::pow(x,-Del)*x1; |
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| 113 | double dir=V*x*x1; |
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| 114 | double per=U2*pp; |
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| 115 | f2 = per + dir; |
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| 116 | //double W2=MN2-MN2*x+Q2/x-Q2; |
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| 117 | //if(W2<W2t) |
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| 118 | //{ |
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| 119 | // per=UU*pp; |
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| 120 | // xf3= per+dir; |
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| 121 | //} |
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| 122 | //else |
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| 123 | xf3= U3*pp+dir; |
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| 124 | fL = per/5.; // 20% |
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| 125 | return; |
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| 126 | } |
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| 127 | |
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| 128 | void getFun(int A, double lx, double Q2, double* f) |
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| 129 | { |
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| 130 | double f2=0., xf3=0., fL=0.; |
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| 131 | if (lx>0.5) G4cerr<<"***getFun: ln(x)="<<lx<<">.5"<<G4endl; |
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| 132 | double x=std::exp(lx); |
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| 133 | double x2=x*x; |
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| 134 | strucf(A, x, Q2, f2, xf3, fL); |
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| 135 | f[0]=f2; // direct part |
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| 136 | f[1]=(-f2+xf3)/x; // *y (neutrino) part |
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| 137 | f[2]=(-f2-xf3)/x; // *y (anti-neutrino) part |
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| 138 | f[3]=(f2-fL-xf3)/x2; // *y2 (neutrino) part |
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| 139 | f[4]=(f2-fL+xf3)/x2; // *y2 (anti-neutrino) part |
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| 140 | } |
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| 141 | |
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| 142 | int main() |
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| 143 | { |
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| 144 | const double reps=.001; // relative accuracy of the total Q2 integral calculation |
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| 145 | const double xeps=.0001; // relative accuracy of the total X integral calculation |
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| 146 | // ========= |
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| 147 | const double GF=1.16637e-5; // Fermi constant in GeV^-2 |
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| 148 | const double GF2=GF*GF; // Squared Fermi constant in GeV^-4 |
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| 149 | const double MW=80.425; // Mass of W-boson in GeV |
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| 150 | const double MW2=MW*MW; // Squared mass of W-boson in GeV^2 |
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| 151 | const double MW4=MW2*MW2; // Quadro mass of W-boson in GeV^4 |
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| 152 | const double hc2=38937932300.;// (hc)^2 in GeV^2*10^-38cm2 to convert GeV^-2 to 10^-38cm2 |
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| 153 | const double pif=3.14159265*4;// 4pi |
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| 154 | const double sik=GF2*hc2/pif; // precalculated coefficient |
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| 155 | //const double mpi=.1349766; // pi0 meson mass in GeV |
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| 156 | //const double mpi=.13957018; // charged pi meson mass in GeV |
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| 157 | //const double mpi2=mpi*mpi; // m_pi^2 in GeV^2 |
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| 158 | const double me=.00051099892; // electron mass in GeV |
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| 159 | const double me2=me*me; // m_e^2 in GeV^2 |
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| 160 | const double hme2=me2/2; // .5*m_e^2 in GeV^2 |
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| 161 | //const double mmu=.105658369; // mu meson mass in GeV |
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| 162 | //const double mmu2=mmu*mmu; // m_mu^2 in GeV^2 |
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| 163 | //const double hmmu2=mmu2/2; // .5*m_mu^2 in GeV^2 |
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| 164 | //const double mtau=1.777; // tau meson mass in GeV |
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| 165 | //const double mtau2=mtau*mtau; // m_tau^2 in GeV^2 |
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| 166 | //const double hmtau2=mtau2/2; // .5*m_e^2 in GeV^2 |
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| 167 | const double mp=.93827203; // proton mass in GeV |
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| 168 | const double mn=.93956536; // neutron mass in GeV |
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| 169 | //const double md=1.87561282; // deuteron mass in GeV |
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| 170 | //const double MN=.931494043; // Nucleon mass (inside nucleus, atomic mass unit, GeV) |
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| 171 | const double MN=(mn+mp)/2; // Nucleon mass (mean free) in GeV |
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| 172 | const double MD=1.232; // proton mass in GeV |
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| 173 | //const double mp2=mp*mp; // m_p^2 in GeV^2 |
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| 174 | const double MN2=MN*MN; // M_N^2 in GeV^2 |
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| 175 | const double dMN=MN+MN; // 2*M_N in GeV |
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| 176 | const double dMN2=MN2+MN2; // 2*M_N^2 in GeV^2 |
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| 177 | const double fMN2=dMN2+dMN2; // 4*M_N^2 in GeV^2 |
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| 178 | const double EminE=me+me2/dMN;// Threshold for muon production |
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| 179 | //const double EminMu=mmu+mmu2/dMN; // Threshold for muon production |
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| 180 | //const double EminTau=mmu+mmu2/dMN; // Threshold for muon production |
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| 181 | // |
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| 182 | //const double mc=.3; // parameter of W>M+mc cut for Quasi-Elastic/Delta |
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| 183 | const double mc=std::sqrt((MN*MN+MD*MD)/2)-MN; // Squared mean between N and \Delta |
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| 184 | //const double mc=mpi; // parameter of W>M+mc cut for Quasi-Elastic/Delta |
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| 185 | const double mcV=(dMN+mc)*mc; // constant of W>M+mc cut for Quasi-Elastic |
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| 186 | //std::ofstream fileNuMuX("NuMuXQ2.out", std::ios::out); |
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| 187 | //fileNuMuX.setf( std::ios::scientific, std::ios::floatfield ); |
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| 188 | // _____ Begin of Test Area |
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| 189 | //Genfun::LogGamma logGamma; |
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| 190 | //double n=4.9; |
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| 191 | //double g=exp(logGamma(n)); |
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| 192 | //G4cout<<"Gamma("<<n<<") = "<<g<<G4endl; |
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| 193 | // ^^^^^ End of Test Area |
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| 194 | // |
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| 195 | double f[5]; // A working array |
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| 196 | int A=12; // Neucleus for which calculations should be done |
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| 197 | double lEnuMin=0; // LogLog of Minimum energy of neutrino |
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| 198 | double lEnuMax=std::log(1.+std::log(300./EminE)); // LogLog of MaximumEnergy of neutrino |
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| 199 | int nE=49; // Number of points |
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| 200 | double dlE=(lEnuMax-lEnuMin)/nE; |
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| 201 | lEnuMin+=dlE/10; |
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| 202 | lEnuMax+=dlE/5; |
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| 203 | G4cout<<"Emin="<<EminE<<",lEi="<<lEnuMin<<",lEa="<<lEnuMax<<",dlE="<<dlE<<G4endl; |
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| 204 | for(double lEnu=lEnuMin; lEnu<lEnuMax; lEnu+=dlE) |
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| 205 | { |
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| 206 | double Enu=std::exp(std::exp(lEnu)-1.)*EminE; // Energy of neutrino/anti-neutrino |
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| 207 | double dEnu=Enu+Enu; // doubled energy of nu/anu |
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| 208 | double Enu2=Enu*Enu; // squared energy of nu/anu |
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| 209 | double Ee=Enu-me; // Free Energy of neutrino/anti-neutrino |
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| 210 | double Ee2=Ee*Ee; // squared energy of nu/anu |
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| 211 | double ME=Enu*MN; // M*E |
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| 212 | double dME=ME+ME; // 2*M*E |
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| 213 | double DIStsig=1.; // Total curent DIS cross-section to be integrated |
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| 214 | double DISmsig=1.e20; // Total remembered DIS cross-section |
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| 215 | double dEMN=(dEnu+MN)*ME; |
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| 216 | double MEm=ME-hme2; |
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| 217 | double sqE=Enu*std::sqrt(MEm*MEm-me2*MN2); |
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| 218 | double E2M=MN*Enu2-(Enu+MN)*hme2; |
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| 219 | double ymax=(E2M+sqE)/dEMN; |
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| 220 | double ymin=(E2M-sqE)/dEMN; |
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| 221 | double rmin=1.-ymin; |
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| 222 | double rhm2E=hme2/Enu2; |
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| 223 | double Q2min=(Enu2+Enu2)*(rmin-rhm2E-std::sqrt(rmin*rmin-rhm2E-rhm2E)); |
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| 224 | double Q2max=dME*ymax; |
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| 225 | int nQ2=8; |
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| 226 | //G4cout<<"*** E="<<Enu<<", Q2i="<<Q2min<<" < Q2a="<<Q2max<<", yi="<<ymin<<" < ya=" |
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| 227 | // <<ymax<<G4endl; |
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| 228 | while(std::fabs(DIStsig-DISmsig)/DIStsig>reps) |
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| 229 | { |
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| 230 | DISmsig=DIStsig; |
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| 231 | DIStsig=0.; |
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| 232 | nQ2*=2; |
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| 233 | double dQ2=(Q2max-Q2min)/nQ2; |
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| 234 | for(double Q2=Q2min+dQ2/2; Q2<Q2max; Q2+=dQ2) |
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| 235 | { |
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| 236 | double DISxint=1.; // Curent DIS x-integral |
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| 237 | double DISmint=1.e20; // Remembered DIS x-integral |
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| 238 | double Q2M=Q2+MW2; |
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| 239 | double dik=MW4/Q2M/Q2M; |
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| 240 | double qmc=Q2+mcV; |
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| 241 | double lXQES=std::log((std::sqrt(qmc*qmc+Q2*fMN2)-qmc)/dMN2);//QuasielasticBoundary |
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| 242 | //double lXQES=log(Q2/(Q2+mcV)); // Quasielastic boundary (W=MN+m_c) |
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| 243 | //double xN=Q2/dME; |
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| 244 | double xN=Q2/MN/(Ee+std::sqrt(Ee2+Q2)); |
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| 245 | //double lXmin=log(xN/ymax); |
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| 246 | double lXmin=std::log(xN); |
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| 247 | // ****** QE ******** |
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| 248 | if(lXQES>lXmin) lXmin=lXQES; // A cut which leaves only QES >>>>>>>>>>>>>>>> |
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| 249 | // *** End of QE^^^^^ |
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| 250 | double lXmax=0.; // QES is in DIS |
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| 251 | //double lXmax=lXQES; // Cut off quasielastic |
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| 252 | int nX=8; |
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| 253 | while(std::fabs(DISxint-DISmint)/DISxint>xeps) |
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| 254 | { |
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| 255 | DISmint=DISxint; |
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| 256 | DISxint=0.; |
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| 257 | nX*=2; |
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| 258 | double dlX=(lXmax-lXmin)/nX; |
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| 259 | for(double lX=lXmin+dlX/2; lX<lXmax; lX+=dlX) |
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| 260 | { |
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| 261 | getFun(A, lX, Q2, f); |
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| 262 | // ***** Neutrino/Antineutrino switch ******>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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| 263 | DISxint+=f[0]+f[0]+xN*(f[1]+f[1]+xN*f[3]); // neutrino |
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| 264 | //DISxint+=f[0]+f[0]+xN*(f[2]+f[2]+xN*f[4]); // anti-neutrino |
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| 265 | //G4cout<<f[0]<<","<<f[1]<<","<<f[2]<<","<<f[3]<<","<<f[4]<<G4endl; |
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| 266 | } |
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| 267 | DISxint*=dlX; |
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| 268 | //G4cout<<"--- E="<<Enu<<" --- Q2="<<Q2<<" --- nX="<<nX<<", iX="<<DISxint |
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| 269 | // <<", mX="<<DISmint<<", rX="<<(DISxint-DISmint)/DISxint<<G4endl; |
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| 270 | } |
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| 271 | //G4cout<<"(E="<<Enu<<"), Q2="<<Q2<<", I="<<DISxint/dik/dik<<G4endl; |
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| 272 | DIStsig+=DISxint*dik; |
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| 273 | } |
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| 274 | DIStsig*=dQ2; |
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| 275 | //G4cout<<"=== E="<<Enu<<" ===> nQ="<<nQ2<<", iQ="<<DIStsig<<", mQ="<<DISmsig |
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| 276 | // <<", rQ="<<(DIStsig-DISmsig)/DIStsig<<G4endl; |
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| 277 | } |
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| 278 | //===== tot/qe choice ==== |
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| 279 | DIStsig*=sik/Enu; |
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| 280 | //G4cout<<"***total-neutrino*** E="<<Enu<<" ,sig/E="<<DIStsig<<G4endl; |
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| 281 | //G4cout<<"***total-antineutrino*** E="<<Enu<<" ,sig/E="<<DIStsig<<G4endl; |
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| 282 | G4cout<<"***quasiel-nu*** E="<<Enu<<" ,sig/E="<<DIStsig*Enu<<G4endl; |
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| 283 | //G4cout<<"***quasiel-antinu*** E="<<Enu<<" ,sig/E="<<DIStsig*Enu<<G4endl; |
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| 284 | //................... |
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| 285 | //DIStsig*=sik; |
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| 286 | //G4cout<<"***qelas*** E="<<Enu<<",sig="<<DIStsig<<G4endl; |
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| 287 | //===== End of the choice |
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| 288 | } // End of the Enery LOOP |
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| 289 | return EXIT_SUCCESS; |
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| 290 | } |
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