EvtDalitzPlot.hh

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//-----------------------------------------------------------------------
// File and Version Information:
//      $Id: EvtDalitzPlot.hh,v 1.1.1.2 2007/10/26 05:03:14 pingrg Exp $
//
// 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:
//      Copyright (C) 1998 Caltech, UCSB
//
// Module creator:
//      Alexei Dvoretskii, Caltech, 2001-2002.
//-----------------------------------------------------------------------
 
#ifndef EVT_DALITZ_PLOT_HH
#define EVT_DALITZ_PLOT_HH
 
#include "EvtCyclic3.hh"
#include "EvtDecayMode.hh"
#include "EvtTwoBodyVertex.hh"
#include <assert.h>
 
class EvtDalitzPlot {
public:
  EvtDalitzPlot();
  EvtDalitzPlot( double mA, double mB, double mC, double bigM, double ldel = 0.,
                 double rdel = 0. );
  EvtDalitzPlot( const EvtDecayMode& mode, double ldel = 0., double rdel = 0. );
  EvtDalitzPlot( const EvtDalitzPlot& other );
  ~EvtDalitzPlot();
  bool                 operator==( const EvtDalitzPlot& other ) const;
  const EvtDalitzPlot* clone() const;
 
  // Absolute limits for masses squared in the Dalitz plot
  // e.g. qAbsMin(0) is the lowest possible value
  // for m2 of particles {12}
 
  double qAbsMin( EvtCyclic3::Pair i ) const;
  double qAbsMax( EvtCyclic3::Pair i ) const;
  double mAbsMin( EvtCyclic3::Pair i ) const;
  double mAbsMax( EvtCyclic3::Pair i ) const;
 
  // Absolute limits for Zemach coordinate qres and qhel (approximate)
  // qHelAbsMin(BC,CA) means absolute minimum for (qCA-qAB)/2.
 
  double        qResAbsMin( EvtCyclic3::Pair i ) const;
  double        qResAbsMax( EvtCyclic3::Pair i ) const;
  double        qHelAbsMin( EvtCyclic3::Pair i ) const;
  double        qHelAbsMax( EvtCyclic3::Pair i ) const;
  inline double qSumMin() const { return sum() + _ldel; }
  inline double qSumMax() const { return sum() + _rdel; }
  inline bool   fuzzy() const { return ( _rdel - _ldel != 0. ); }
 
  // Find the area of the Dalitz plot by numeric integration. (N bins for variable q(i) are
  // used). Very large numbers of N can result in a very long calculation. It should not matter
  // which two pairs f variables are used. The integral should eventually converge to the same
  // number
 
  double getArea( int N = 1000, EvtCyclic3::Pair i = EvtCyclic3::AB,
                  EvtCyclic3::Pair j = EvtCyclic3::BC ) const;
 
  // Limits for masses squared when one mass squared is known
 
  double qMin( EvtCyclic3::Pair i, EvtCyclic3::Pair j, double q ) const;
  double qMax( EvtCyclic3::Pair i, EvtCyclic3::Pair j, double q ) const;
 
  // Coordinate transformations
 
  double cosTh( EvtCyclic3::Pair i1, double q1, EvtCyclic3::Pair i2, double q2 ) const;
  double e( EvtCyclic3::Index i, EvtCyclic3::Pair j, double q ) const;
  double p( EvtCyclic3::Index i, EvtCyclic3::Pair j, double q ) const;
 
  double q( EvtCyclic3::Pair i1, double cosTh, EvtCyclic3::Pair i2, double q2 ) const;
 
  // |J| of transformation of qi to cosTh in the rest-frame of j
 
  double jacobian( EvtCyclic3::Pair i, double q ) const;
 
  // Given resonance index and mass returns decay
  // and birth vertices
 
  EvtTwoBodyVertex vD( EvtCyclic3::Pair iRes, double m0, int L ) const;
  EvtTwoBodyVertex vB( EvtCyclic3::Pair iRes, double m0, int L ) const;
 
  // Accessors
 
  double        sum() const;
  inline double bigM() const { return _bigM; }
  inline double mA() const { return _mA; }
  inline double mB() const { return _mB; }
  inline double mC() const { return _mC; }
  double        m( EvtCyclic3::Index i ) const;
 
  void print() const;
 
  void sanityCheck() const;
 
protected:
  // Defines two dimensional dalitz plot
 
  double _mA;
  double _mB;
  double _mC;
  double _bigM;
 
  // Defines third dimension, or fuzziness. M^2 + ldel < M^2 < M^2 + rdel
 
  double _ldel;
  double _rdel;
};
 
#endif