1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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4 | // * * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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10 | // * * |
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11 | // * Neither the authors of this software system, nor their employing * |
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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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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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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 | #ifndef G4QPomeron_h |
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27 | #define G4QPomeron_h 1 |
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28 | // |
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29 | // $Id: G4QPomeron.hh,v 1.2 2006/12/12 11:02:22 mkossov Exp $ |
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30 | // GEANT4 tag $Name: $ |
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31 | // |
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32 | // ------------------------------------------------------------ |
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33 | // GEANT 4 class implementation file |
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34 | // |
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35 | // ---------------- G4QPomeron ---------------- |
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36 | // by Mikhail Kossov Oct, 2006 |
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37 | // class for a Pomeron used by Parton String Models |
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38 | // For comparison mirror member functions are taken from G4 class: |
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39 | // G4PomeronCrossSection |
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40 | // ------------------------------------------------------------ |
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41 | |
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42 | #include "globals.hh" |
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43 | |
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44 | class G4QPomeron |
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45 | { |
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46 | public: |
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47 | G4QPomeron(G4int PDGCode = 211); |
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48 | ~G4QPomeron(){;} |
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49 | void Pomeron_S(G4double apomeron_S) {pomeron_S = apomeron_S;} |
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50 | void Pomeron_Gamma(G4double apomeron_Gamma) {pomeron_Gamma = apomeron_Gamma;} |
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51 | void Pomeron_C(G4double apomeron_C) {pomeron_C = apomeron_C;} |
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52 | void Pomeron_Rsquare(G4double apomeron_Rsquare) {pomeron_Rsquare = apomeron_Rsquare;} |
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53 | void Pomeron_Alpha(G4double apomeron_Alpha) {pomeron_Alpha = apomeron_Alpha;} |
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54 | void Pomeron_Alphaprime(G4double apom_Alphaprime){pomeron_Alphaprime = apom_Alphaprime;} |
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55 | void Pomeron_Gamma_Hard(G4double apom_Gamma_Hard){pomeron_Gamma_Hard = apom_Gamma_Hard;} |
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56 | void Pomeron_Alpha_Hard(G4double apom_Alpha_Hard){pomeron_Alpha_Hard = apom_Alpha_Hard;} |
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57 | G4double GetTotalCrossSection(const G4double s) {return SigP(s) * Expand(Z(s)/2);} |
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58 | G4double GetDiffractiveCrossSection(const G4double s) |
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59 | {return SigP(s)/pomeron_C*(Expand(Z(s)/2)-Expand(Z(s)));} |
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60 | G4double GetElasticCrossSection(const G4double s) |
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61 | {return (pomeron_C-1)*GetElasticCrossSection(s);} |
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62 | G4double GetInelasticCrossSection(const G4double s) |
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63 | {return GetTotalCrossSection(s)-GetElasticCrossSection(s);} |
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64 | G4double GetTotalProbability(const G4double s, const G4double imp2) |
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65 | {return 2*(1-std::exp(-Eikonal(s,imp2)))/pomeron_C*(1-std::exp(-Eikonal(s,imp2)));} |
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66 | G4double GetDiffractiveProbability(const G4double s, const G4double imp2) |
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67 | {return (pomeron_C-1.)/pomeron_C*(GetTotalProbability(s,imp2) - |
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68 | GetNondiffractiveProbability(s,imp2));} |
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69 | G4double GetNondiffractiveProbability(const G4double s, const G4double imp2) |
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70 | {return (1.-std::exp(-2*Eikonal(s,imp2)))/pomeron_C;} |
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71 | G4double GetElasticProbability(const G4double s, const G4double imp2) |
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72 | {return GetTotalProbability(s,imp2)-GetInelasticProbability(s,imp2);} |
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73 | G4double GetInelasticProbability(const G4double s, const G4double imp2) |
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74 | {return GetNondiffractiveProbability(s,imp2)+GetDiffractiveProbability(s,imp2);} |
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75 | G4double GetCutPomeronProbability(const G4double s,const G4double ip2, const G4int nPom); |
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76 | void SetGamma(const G4double agam) {pomeron_Gamma=agam/GeV/GeV;} // @@ Temporary |
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77 | G4double SoftEikonal(G4double s, G4double imp2) |
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78 | {return Zsoft(s)/2*std::exp(-imp2/LambdaSoft(s)/hbarc_squared/4);} |
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79 | G4double HardEikonal(G4double s, G4double imp2) |
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80 | {return Zhard(s)/2*std::exp(-imp2/LambdaHard(s)/hbarc_squared/4);} |
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81 | private: |
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82 | G4double PowerSoft(const G4double s) |
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83 | {return pomeron_Gamma*std::pow(s/pomeron_S, pomeron_Alpha-1.);} |
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84 | G4double PowerHard(const G4double s) |
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85 | {return pomeron_Gamma_Hard*std::pow(s/pomeron_S, pomeron_Alpha_Hard-1.);} |
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86 | G4double LambdaSoft(const G4double s) |
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87 | {return pomeron_Rsquare+pomeron_Alphaprime*std::log(s/pomeron_S);} |
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88 | G4double LambdaHard(const G4double){return pomeron_Rsquare;} // @@ ? M.K. |
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89 | G4double Zsoft(const G4double s) {return 2*pomeron_C*PowerSoft(s)/LambdaSoft(s);} |
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90 | G4double Zhard(const G4double s) {return 2*pomeron_C*PowerHard(s)/LambdaHard(s);} |
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91 | |
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92 | void InitForNucleon(); |
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93 | void InitForPion(); |
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94 | void InitForKaon(); |
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95 | void InitForGamma(); |
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96 | |
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97 | G4double Expand(G4double z); |
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98 | G4double Z(const G4double Scms) {return 2*pomeron_C*Power(s)/Lambda(Scms);} |
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99 | G4double SigP(const G4double Scms) {return 8*pi*hbarc_squared*Power(Scms);} |
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100 | G4double Power(const G4double Scms) |
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101 | {return pomeron_Gamma*std::pow(Scms/pomeron_S,pomeron_Alpha-1);} |
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102 | G4double Lambda(const G4double s) |
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103 | {return pomeron_Rsquare+pomeron_Alphaprime*std::log(s/pomeron_S);} |
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104 | G4double Eikonal(const G4double s, const G4double imp2) |
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105 | {return std::exp(-imp2/(4*Lambda(s)*hbarc_squared))*Z(s)/2;} |
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106 | // Body |
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107 | G4double pomeron_S; |
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108 | G4double pomeron_Gamma; |
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109 | G4double pomeron_C; |
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110 | G4double pomeron_Rsquare; |
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111 | G4double pomeron_Alpha; |
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112 | G4double pomeron_Alphaprime; |
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113 | G4double pomeron_Gamma_Hard; |
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114 | G4double pomeron_Alpha_Hard; |
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115 | }; |
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116 | #endif |
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