include/Geant4/G4FermiPhaseSpaceDecay.hh

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0025 //
0026 //
0027 // Hadronic Process: Phase space decay for the Fermi BreakUp model
0028 // by V. Lara
0029 //
0030 // Modifications:
0031 // 01.04.2011 General cleanup by V.Ivanchenko:
0032 //          - IsotropicVector is inlined
0033 //          - Momentum computation return zero or positive value
0034 //          - DumpProblem method is added providing more information
0035 //          - Reduced usage of exotic std functions
0036 //
0037
0038 #ifndef G4FermiPhaseSpaceDecay_hh
0039 #define G4FermiPhaseSpaceDecay_hh 1
0040
0041 #include "G4LorentzVector.hh"
0042 #include "G4ThreeVector.hh"
0043 #include "Randomize.hh"
0044
0045 #include <vector>
0046
0047 class G4Pow;
0048
0049 class G4FermiPhaseSpaceDecay
0050 {
0051 public:
0052
0053   G4FermiPhaseSpaceDecay();
0054   ~G4FermiPhaseSpaceDecay();
0055
0056   std::vector<G4LorentzVector*>* Decay(G4double parent_mass,
0057     const std::vector<G4double>& fragment_masses) const;
0058
0059 private:
0060
0061   inline G4double PtwoBody(G4double E, G4double P1, G4double P2) const;
0062
0063   G4double BetaKopylov(G4int, CLHEP::HepRandomEngine*) const;
0064
0065   std::vector<G4LorentzVector*> *
0066   KopylovNBodyDecay(G4double, const std::vector<G4double>&) const;
0067
0068   G4FermiPhaseSpaceDecay(const G4FermiPhaseSpaceDecay&) = delete;
0069   const G4FermiPhaseSpaceDecay & operator=
0070   (const G4FermiPhaseSpaceDecay &) = delete;
0071   G4bool operator==(const G4FermiPhaseSpaceDecay&) = delete;
0072   G4bool operator!=(const G4FermiPhaseSpaceDecay&) = delete;
0073
0074   G4Pow* g4calc;
0075 };
0076
0077 inline G4double
0078 G4FermiPhaseSpaceDecay::PtwoBody(G4double E, G4double P1, G4double P2) const
0079 {
0080   G4double P = (E+P1+P2)*(E+P1-P2)*(E-P1+P2)*(E-P1-P2)/(4.0*E*E);
0081   return (P>0.0) ? std::sqrt(P) : 0.0;
0082 }
0083
0084 #endif