EvtFlatte.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/EvtFlatte.hh
//
// Description:resonance-defining class
//
// Modification history:
//
//    ponyisi  18 Feb 2008  created
//
//------------------------------------------------------------------------
 
#ifndef EVTFLATTE_HH
#define EVTFLATTE_HH
 
#include "EvtComplex.hh"
#include "EvtVector4R.hh"
#include "TComplex.h"
#include <vector>
 
using std::vector;
 
// Helper class
 
class EvtFlatteParam {
public:
  EvtFlatteParam( double m1, double m2, double g ) : _m1( m1 ), _m2( m2 ), _g( g ) {}
 
  inline double m1() const { return _m1; }
  inline double m2() const { return _m2; }
  inline double g() const { return _g; }
 
private:
  double _m1, _m2, _g;
};
 
// class declaration
 
class EvtFlatte {
public:
  // operator
  EvtFlatte& operator=( const EvtFlatte& );
 
  // constructor with all information about the resonance
  EvtFlatte( const EvtVector4R& p4_p, const EvtVector4R& p4_d1, const EvtVector4R& p4_d2,
             double ampl, double theta, double mass, vector<EvtFlatteParam>& params
             //           double m1a = 0.0, double m1b = 0.0, double g1 = 0.0,
             //           double m2a = 0.0, double m2b = 0.0, double g2 = 0.0
  );
 
  // destructor
  virtual ~EvtFlatte();
 
  // 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 bwm
  inline double mass() { return _mass; }
 
  // functions
 
  // calculate amplitude for this resonance
  EvtComplex resAmpl();
 
private:
  inline EvtComplex sqrtCplx( double in ) {
    return ( in > 0 ) ? EvtComplex( sqrt( in ), 0 ) : EvtComplex( 0, sqrt( -in ) );
  }
 
  EvtVector4R            _p4_p, _p4_d1, _p4_d2;
  double                 _ampl, _theta, _mass;
  vector<EvtFlatteParam> _params;
  //      double _m1a, _m1b, _g1;
  //      double _m2a, _m2b, _g2;
};
 
#endif