[819] | 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 | #ifndef G4QPomeron_h |
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| 27 | #define G4QPomeron_h 1 |
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| 28 | // |
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[1055] | 29 | // $Id: G4QPomeron.hh,v 1.3 2009/02/23 09:49:24 mkossov Exp $ |
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| 30 | // GEANT4 tag $Name: geant4-09-03-beta-cand-01 $ |
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[819] | 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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[1055] | 41 | // Short description: Pomeron is one of the possible vacuum pole (the |
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| 42 | // second is Oderon, but they are identical in the present model), by |
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| 43 | // which particle exchang in the ellastic scattering process. Strings, |
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| 44 | // which appear as a cut of the Pomeron (optic theorem connects the |
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| 45 | // amplitude of scattering at zero angle with the total inelastic |
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| 46 | // cross-section), describe most of the processes at high energies. |
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| 47 | // ------------------------------------------------------------------ |
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[819] | 48 | |
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| 49 | #include "globals.hh" |
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| 50 | |
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| 51 | class G4QPomeron |
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| 52 | { |
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| 53 | public: |
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| 54 | G4QPomeron(G4int PDGCode = 211); |
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| 55 | ~G4QPomeron(){;} |
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| 56 | void Pomeron_S(G4double apomeron_S) {pomeron_S = apomeron_S;} |
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| 57 | void Pomeron_Gamma(G4double apomeron_Gamma) {pomeron_Gamma = apomeron_Gamma;} |
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| 58 | void Pomeron_C(G4double apomeron_C) {pomeron_C = apomeron_C;} |
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| 59 | void Pomeron_Rsquare(G4double apomeron_Rsquare) {pomeron_Rsquare = apomeron_Rsquare;} |
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| 60 | void Pomeron_Alpha(G4double apomeron_Alpha) {pomeron_Alpha = apomeron_Alpha;} |
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| 61 | void Pomeron_Alphaprime(G4double apom_Alphaprime){pomeron_Alphaprime = apom_Alphaprime;} |
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| 62 | void Pomeron_Gamma_Hard(G4double apom_Gamma_Hard){pomeron_Gamma_Hard = apom_Gamma_Hard;} |
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| 63 | void Pomeron_Alpha_Hard(G4double apom_Alpha_Hard){pomeron_Alpha_Hard = apom_Alpha_Hard;} |
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| 64 | G4double GetTotalCrossSection(const G4double s) {return SigP(s) * Expand(Z(s)/2);} |
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| 65 | G4double GetDiffractiveCrossSection(const G4double s) |
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| 66 | {return SigP(s)/pomeron_C*(Expand(Z(s)/2)-Expand(Z(s)));} |
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| 67 | G4double GetElasticCrossSection(const G4double s) |
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| 68 | {return (pomeron_C-1)*GetElasticCrossSection(s);} |
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| 69 | G4double GetInelasticCrossSection(const G4double s) |
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| 70 | {return GetTotalCrossSection(s)-GetElasticCrossSection(s);} |
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| 71 | G4double GetTotalProbability(const G4double s, const G4double imp2) |
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| 72 | {return 2*(1-std::exp(-Eikonal(s,imp2)))/pomeron_C*(1-std::exp(-Eikonal(s,imp2)));} |
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[1055] | 73 | G4double GetDiffractiveProbability(const G4double s, const G4double imp2) |
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[819] | 74 | {return (pomeron_C-1.)/pomeron_C*(GetTotalProbability(s,imp2) - |
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| 75 | GetNondiffractiveProbability(s,imp2));} |
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[1055] | 76 | G4double GetNondiffractiveProbability(const G4double s, const G4double imp2) |
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[819] | 77 | {return (1.-std::exp(-2*Eikonal(s,imp2)))/pomeron_C;} |
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| 78 | G4double GetElasticProbability(const G4double s, const G4double imp2) |
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| 79 | {return GetTotalProbability(s,imp2)-GetInelasticProbability(s,imp2);} |
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| 80 | G4double GetInelasticProbability(const G4double s, const G4double imp2) |
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| 81 | {return GetNondiffractiveProbability(s,imp2)+GetDiffractiveProbability(s,imp2);} |
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| 82 | G4double GetCutPomeronProbability(const G4double s,const G4double ip2, const G4int nPom); |
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| 83 | void SetGamma(const G4double agam) {pomeron_Gamma=agam/GeV/GeV;} // @@ Temporary |
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| 84 | G4double SoftEikonal(G4double s, G4double imp2) |
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| 85 | {return Zsoft(s)/2*std::exp(-imp2/LambdaSoft(s)/hbarc_squared/4);} |
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| 86 | G4double HardEikonal(G4double s, G4double imp2) |
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| 87 | {return Zhard(s)/2*std::exp(-imp2/LambdaHard(s)/hbarc_squared/4);} |
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| 88 | private: |
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| 89 | G4double PowerSoft(const G4double s) |
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| 90 | {return pomeron_Gamma*std::pow(s/pomeron_S, pomeron_Alpha-1.);} |
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| 91 | G4double PowerHard(const G4double s) |
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| 92 | {return pomeron_Gamma_Hard*std::pow(s/pomeron_S, pomeron_Alpha_Hard-1.);} |
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| 93 | G4double LambdaSoft(const G4double s) |
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| 94 | {return pomeron_Rsquare+pomeron_Alphaprime*std::log(s/pomeron_S);} |
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| 95 | G4double LambdaHard(const G4double){return pomeron_Rsquare;} // @@ ? M.K. |
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| 96 | G4double Zsoft(const G4double s) {return 2*pomeron_C*PowerSoft(s)/LambdaSoft(s);} |
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| 97 | G4double Zhard(const G4double s) {return 2*pomeron_C*PowerHard(s)/LambdaHard(s);} |
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| 98 | |
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| 99 | void InitForNucleon(); |
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| 100 | void InitForPion(); |
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| 101 | void InitForKaon(); |
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| 102 | void InitForGamma(); |
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[1055] | 103 | |
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[819] | 104 | G4double Expand(G4double z); |
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| 105 | G4double Z(const G4double Scms) {return 2*pomeron_C*Power(s)/Lambda(Scms);} |
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| 106 | G4double SigP(const G4double Scms) {return 8*pi*hbarc_squared*Power(Scms);} |
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| 107 | G4double Power(const G4double Scms) |
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[1055] | 108 | {return pomeron_Gamma*std::pow(Scms/pomeron_S,pomeron_Alpha-1);} |
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[819] | 109 | G4double Lambda(const G4double s) |
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| 110 | {return pomeron_Rsquare+pomeron_Alphaprime*std::log(s/pomeron_S);} |
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| 111 | G4double Eikonal(const G4double s, const G4double imp2) |
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| 112 | {return std::exp(-imp2/(4*Lambda(s)*hbarc_squared))*Z(s)/2;} |
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| 113 | // Body |
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| 114 | G4double pomeron_S; |
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| 115 | G4double pomeron_Gamma; |
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| 116 | G4double pomeron_C; |
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| 117 | G4double pomeron_Rsquare; |
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| 118 | G4double pomeron_Alpha; |
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| 119 | G4double pomeron_Alphaprime; |
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| 120 | G4double pomeron_Gamma_Hard; |
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| 121 | G4double pomeron_Alpha_Hard; |
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| 122 | }; |
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| 123 | #endif |
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