include/Geant4/G4SampleResonance.hh

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0025 //
0026
0027 #ifndef G4SampleResonance_h
0028 #define G4SampleResonance_h 1
0029
0030 // ------------------------------------------------------------
0031 //      GEANT 4 class header file
0032 //
0033 //      ---------------- G4SampleResonance ----------------
0034 //             by Henning Weber, March 2001.
0035 //      helper class for sampling resonance masses
0036 // ------------------------------------------------------------
0037
0038 #include "globals.hh"
0039 #include <map>
0040 #include "G4ParticleDefinition.hh"
0041 #include "G4Log.hh"
0042
0043 class G4SampleResonance
0044 {
0045 public:
0046
0047   G4double GetMinimumMass(const G4ParticleDefinition* p) const;
0048   G4double SampleMass(const G4double poleMass,
0049               const G4double gamma,
0050               const G4double minMass,
0051               const G4double maxMass) const;
0052   G4double SampleMass(const G4ParticleDefinition* p, const G4double maxMass) const;
0053
0054 private:
0055
0056   G4double BrWigInt0(const G4double x, const G4double gamma, const G4double m0) const
0057     { return 2.0*gamma*std::atan( 2.0 * (x-m0)/ gamma  ); }
0058
0059   G4double BrWigInt1(const G4double x, const G4double gamma, const G4double m0) const
0060     { return 0.5*gamma*gamma*G4Log( (x-m0)*(x-m0)+gamma*gamma/4.0 ) + m0*BrWigInt0(x,gamma,m0); }
0061
0062   G4double BrWigInv(const G4double x, const G4double gamma, const G4double m0) const
0063     { return 0.5*gamma*std::tan( 0.5*x/gamma )+m0; }
0064
0065 public:
0066
0067   typedef std::map<const G4ParticleDefinition*, G4double, std::less<const G4ParticleDefinition*> >::const_iterator minMassMapIterator;
0068   typedef std::map<const G4ParticleDefinition*, G4double, std::less<const G4ParticleDefinition*> > minMassMapType;
0069
0070 private:
0071
0072   static G4ThreadLocal minMassMapType *minMassCache_G4MT_TLS_;
0073
0074 };
0075
0076
0077 #endif
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