EvtResonance.hh

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//--------------------------------------------------------------------------
//
// Environment:
//      This software is part of the EvtGen package developed jointly
//      for the BaBar and CLEO collaborations.  If you use all or part
//      of it, please give an appropriate acknowledgement.
//
// Copyright Information: See EvtGen/COPYRIGHT
//      Copyright (C) 1998      Caltech, UCSB
//
// Module: EvtGen/EvtResonance.hh
//
// Description:resonance-defining class
//
// Modification history:
//
//    NK     September 4, 1997         Module created
//
//------------------------------------------------------------------------
 
#ifndef EVTRESONANCE_HH
#define EVTRESONANCE_HH
 
#include "EvtGenBase/EvtVector4R.hh"
 
class EvtComplex;
 
 
//class declaration
 
class EvtResonance {
  public:
 
   //operator
   EvtResonance& operator = (const EvtResonance &);
 
   //constructor with all information about the resonance
   EvtResonance(const EvtVector4R& p4_p, const EvtVector4R& p4_d1, 
        const EvtVector4R& p4_d2, 
        double ampl = 0.0, double theta = 0.0, double gamma = 0.0, 
        double bwm = 0.0, int spin = 0);
 
    //destructor
   virtual ~EvtResonance();
 
   //accessors
      //return 4-momenta of the particles involved
    inline const EvtVector4R& p4_p() { return _p4_p; }
    inline const EvtVector4R& p4_d1() { return _p4_d1; }
    inline const EvtVector4R& p4_d2() { return _p4_d2; }  
    
 
     //return amplitude
    inline double amplitude() { return _ampl; }  
 
      //return theta
    inline double theta() { return _theta; } 
 
      //return gamma
    inline double gamma() { return _gamma; } 
 
      //return bwm
    inline double bwm() { return _bwm; } 
 
       //return spin
    inline int spin() { return _spin; } 
 
//functions
 
      //calculate amplitude for this resonance
     EvtComplex resAmpl();
 
     //calculate relativistic Breit-Wigner amplitude for P-decays of scalars
     EvtComplex relBrWig(int i);
   
  private:
 
    EvtVector4R _p4_p, _p4_d1, _p4_d2;
    double _ampl, _theta, _gamma, _bwm;
    int _spin;
}; 
 
#endif