TCrossPart.h

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#ifndef RAD_TCrossPart
#define RAD_TCrossPart
 
#include "TDFun_o.h"
#include "TGenPhaseSpace.h"
#include "TLorentzVector.h"
#include "TLorentzVectorC.h"
#include "TPhoton_o.h"
 
const size_t NPARTMAX = 5;
class TCrossPart {
protected:
  TGenPhaseSpace   fevent;
  rb::TPhoton*     fphot;
  rb::TPhotonD*    fsphot;
  rb::TDFun*       fD;
  double           fe; // Beam energy
  double           fs; // (2*e)^2
  double           flogs;
  double           fbeta2;
  double           fdelta;  // soft and virtual photon energy cut
  double           fK;      // K-factor
  double           fep;     // positron energy
  double           fem;     // electron energy
  double           fsigmap; // positron energy spread
  double           fsigmam; // electron energy spread
  double           fppz;    // positron momentum
  double           fpmz;    // electron momentum
  bool             fBeamSpread;
  double           fsum[NPARTMAX];
  double           fsum2[NPARTMAX];
  double           fmin[NPARTMAX]; // minimum cross section
  double           fmax[NPARTMAX]; // maximum cross section
  size_t           fN[NPARTMAX];   // number of events to calculate cross section
  double           fcs[NPARTMAX];
  double           fecs[NPARTMAX];
  double           facs[NPARTMAX]; // parts of total cross section for generation
  double           fxm;            // Energy of photon emmitted by electron
  double           fxp;            // Energy of photon emmitted by positron
  bool             inc[NPARTMAX];
  size_t           fNRad;       // Minimal number of generated events for integral calculation
  TLorentzVector   fpp;         // inital momentum of positron
  TLorentzVector   fpm;         // inital momentum of electron
  TLorentzVector   fW;          // momentum in cm
  TLorentzVector   fq;          // momentum in cm after photons emission
  TLorentzVectorC  fJc;         // hadronic current (complex)
  size_t           fNfinal;     // number of final particles
  TLorentzVector** fres;        // pointers to output particles
  double           fm[7];       // masses of final particle
  int              fpid[7 + 2]; // pid of particles according to PDG
  double           fq2;         // square momentum in cm after photon emission
  double           radB( const TLorentzVector& k ); // Bremsstrahlung
  double           rad( double zp, double zm );     // Collinear region emmision
  void             SetFinalParticles( size_t, const double*, const int* );
  double           Generate();
  virtual void     SetJ()     = 0; // Set hadronic current
  virtual bool     Accepted() = 0;
  void             J3PseudoScalars();
 
public:
  TCrossPart( double e, double de, double nth0 );
  virtual ~TCrossPart();
 
  double GetValue( const unsigned int npart ); // Generate events of part npart
  void   MakeParts( double err ); // Calculate cross sections of parts with precision err
  size_t GenUnWeightedEvent();
  size_t GenWeightedEvent( double& w );
  TLorentzVector** GetParticles() { return fres; }
  void             SetNRad( size_t x = 25000 ) { fNRad = x; }
  size_t           GetNRad() { return fNRad; }
  size_t           GetNfinal() { return fNfinal; }
  int              GetPid( size_t i ) { return fpid[i]; }
  void             BeamSpread();
  void             SetBeamSpread( double x = 1 ) { // beam spread in MeV
    fBeamSpread = true;
    fsigmap     = x;
    fsigmam     = x;
  }
};
 
#endif // RAD_TCrossPart