// // ******************************************************************** // * License and Disclaimer * // * * // * The Geant4 software is copyright of the Copyright Holders of * // * the Geant4 Collaboration. It is provided under the terms and * // * conditions of the Geant4 Software License, included in the file * // * LICENSE and available at http://cern.ch/geant4/license . These * // * include a list of copyright holders. * // * * // * Neither the authors of this software system, nor their employing * // * institutes,nor the agencies providing financial support for this * // * work make any representation or warranty, express or implied, * // * regarding this software system or assume any liability for its * // * use. Please see the license in the file LICENSE and URL above * // * for the full disclaimer and the limitation of liability. * // * * // * This code implementation is the result of the scientific and * // * technical work of the GEANT4 collaboration. * // * By using, copying, modifying or distributing the software (or * // * any work based on the software) you agree to acknowledge its * // * use in resulting scientific publications, and indicate your * // * acceptance of all terms of the Geant4 Software license. * // ******************************************************************** // #ifndef G4QPomeron_h #define G4QPomeron_h 1 // // $Id: G4QPomeron.hh,v 1.3 2009/02/23 09:49:24 mkossov Exp $ // GEANT4 tag $Name: geant4-09-03-beta-cand-01 $ // // ------------------------------------------------------------ // GEANT 4 class implementation file // // ---------------- G4QPomeron ---------------- // by Mikhail Kossov Oct, 2006 // class for a Pomeron used by Parton String Models // For comparison mirror member functions are taken from G4 class: // G4PomeronCrossSection // ------------------------------------------------------------ // Short description: Pomeron is one of the possible vacuum pole (the // second is Oderon, but they are identical in the present model), by // which particle exchang in the ellastic scattering process. Strings, // which appear as a cut of the Pomeron (optic theorem connects the // amplitude of scattering at zero angle with the total inelastic // cross-section), describe most of the processes at high energies. // ------------------------------------------------------------------ #include "globals.hh" class G4QPomeron { public: G4QPomeron(G4int PDGCode = 211); ~G4QPomeron(){;} void Pomeron_S(G4double apomeron_S) {pomeron_S = apomeron_S;} void Pomeron_Gamma(G4double apomeron_Gamma) {pomeron_Gamma = apomeron_Gamma;} void Pomeron_C(G4double apomeron_C) {pomeron_C = apomeron_C;} void Pomeron_Rsquare(G4double apomeron_Rsquare) {pomeron_Rsquare = apomeron_Rsquare;} void Pomeron_Alpha(G4double apomeron_Alpha) {pomeron_Alpha = apomeron_Alpha;} void Pomeron_Alphaprime(G4double apom_Alphaprime){pomeron_Alphaprime = apom_Alphaprime;} void Pomeron_Gamma_Hard(G4double apom_Gamma_Hard){pomeron_Gamma_Hard = apom_Gamma_Hard;} void Pomeron_Alpha_Hard(G4double apom_Alpha_Hard){pomeron_Alpha_Hard = apom_Alpha_Hard;} G4double GetTotalCrossSection(const G4double s) {return SigP(s) * Expand(Z(s)/2);} G4double GetDiffractiveCrossSection(const G4double s) {return SigP(s)/pomeron_C*(Expand(Z(s)/2)-Expand(Z(s)));} G4double GetElasticCrossSection(const G4double s) {return (pomeron_C-1)*GetElasticCrossSection(s);} G4double GetInelasticCrossSection(const G4double s) {return GetTotalCrossSection(s)-GetElasticCrossSection(s);} G4double GetTotalProbability(const G4double s, const G4double imp2) {return 2*(1-std::exp(-Eikonal(s,imp2)))/pomeron_C*(1-std::exp(-Eikonal(s,imp2)));} G4double GetDiffractiveProbability(const G4double s, const G4double imp2) {return (pomeron_C-1.)/pomeron_C*(GetTotalProbability(s,imp2) - GetNondiffractiveProbability(s,imp2));} G4double GetNondiffractiveProbability(const G4double s, const G4double imp2) {return (1.-std::exp(-2*Eikonal(s,imp2)))/pomeron_C;} G4double GetElasticProbability(const G4double s, const G4double imp2) {return GetTotalProbability(s,imp2)-GetInelasticProbability(s,imp2);} G4double GetInelasticProbability(const G4double s, const G4double imp2) {return GetNondiffractiveProbability(s,imp2)+GetDiffractiveProbability(s,imp2);} G4double GetCutPomeronProbability(const G4double s,const G4double ip2, const G4int nPom); void SetGamma(const G4double agam) {pomeron_Gamma=agam/GeV/GeV;} // @@ Temporary G4double SoftEikonal(G4double s, G4double imp2) {return Zsoft(s)/2*std::exp(-imp2/LambdaSoft(s)/hbarc_squared/4);} G4double HardEikonal(G4double s, G4double imp2) {return Zhard(s)/2*std::exp(-imp2/LambdaHard(s)/hbarc_squared/4);} private: G4double PowerSoft(const G4double s) {return pomeron_Gamma*std::pow(s/pomeron_S, pomeron_Alpha-1.);} G4double PowerHard(const G4double s) {return pomeron_Gamma_Hard*std::pow(s/pomeron_S, pomeron_Alpha_Hard-1.);} G4double LambdaSoft(const G4double s) {return pomeron_Rsquare+pomeron_Alphaprime*std::log(s/pomeron_S);} G4double LambdaHard(const G4double){return pomeron_Rsquare;} // @@ ? M.K. G4double Zsoft(const G4double s) {return 2*pomeron_C*PowerSoft(s)/LambdaSoft(s);} G4double Zhard(const G4double s) {return 2*pomeron_C*PowerHard(s)/LambdaHard(s);} void InitForNucleon(); void InitForPion(); void InitForKaon(); void InitForGamma(); G4double Expand(G4double z); G4double Z(const G4double Scms) {return 2*pomeron_C*Power(s)/Lambda(Scms);} G4double SigP(const G4double Scms) {return 8*pi*hbarc_squared*Power(Scms);} G4double Power(const G4double Scms) {return pomeron_Gamma*std::pow(Scms/pomeron_S,pomeron_Alpha-1);} G4double Lambda(const G4double s) {return pomeron_Rsquare+pomeron_Alphaprime*std::log(s/pomeron_S);} G4double Eikonal(const G4double s, const G4double imp2) {return std::exp(-imp2/(4*Lambda(s)*hbarc_squared))*Z(s)/2;} // Body G4double pomeron_S; G4double pomeron_Gamma; G4double pomeron_C; G4double pomeron_Rsquare; G4double pomeron_Alpha; G4double pomeron_Alphaprime; G4double pomeron_Gamma_Hard; G4double pomeron_Alpha_Hard; }; #endif