EvtAmpAmpPdf.hh

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/*******************************************************************************
 * Project: BaBar detector at the SLAC PEP-II B-factory
 * Package: EvtGenBase
 *    File: $Id: EvtAmpAmpPdf.hh,v 1.1.1.2 2007/10/26 05:03:14 pingrg Exp $
 *  Author: Alexei Dvoretskii, dvoretsk@slac.stanford.edu, 2001-2002
 *
 * Copyright (C) 2002 Caltech
 *******************************************************************************/
 
#ifndef EVT_AMP_AMP_PDF_HH
#define EVT_AMP_AMP_PDF_HH
 
// From the product A1A2* four PDF terms can be constructed, by taking the positive
// and the negative parts or the real and imaginary part of the product.
 
#include "EvtAmplitude.hh"
#include "EvtMacros.hh"
#include "EvtPdf.hh"
#include <assert.h>
 
enum { POSRE = 0, NEGRE, POSIM, NEGIM };
 
template <class T> class EvtAmpAmpPdf : public EvtPdf<T> {
public:
  EvtAmpAmpPdf() {}
  EvtAmpAmpPdf( int type, const EvtAmplitude<T>& amp1, const EvtAmplitude<T>& amp2 )
      : EvtPdf<T>(), _type( type ), _amp1( amp1.clone() ), _amp2( amp2.clone() ) {}
  EvtAmpAmpPdf( const EvtAmpAmpPdf<T>& other )
      : EvtPdf<T>( other ), _type( other._type ), COPY_PTR( _amp1 ), COPY_PTR( _amp2 ) {}
  virtual ~EvtAmpAmpPdf() {
    delete _amp1;
    delete _amp2;
  }
 
  virtual EvtAmpAmpPdf<T>* clone() const { return new EvtAmpAmpPdf( *this ); }
 
  virtual double pdf( const T& p ) const {
    EvtComplex amp1 = _amp1->evaluate( p );
    EvtComplex amp2 = _amp2->evaluate( p );
    EvtComplex pr   = amp1 * conj( amp2 );
 
    if ( _type == POSRE ) return real( pr ) > 0 ? real( pr ) : 0.;
    if ( _type == NEGRE ) return real( pr ) < 0 ? -real( pr ) : 0.;
    if ( _type == POSIM ) return imag( pr ) > 0 ? imag( pr ) : 0.;
    if ( _type == NEGIM ) return imag( pr ) < 0 ? -imag( pr ) : 0.;
 
    assert( 0 );
  }
 
private:
  int              _type;
  EvtAmplitude<T>* _amp1;
  EvtAmplitude<T>* _amp2;
};
 
#endif