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 "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