/*****************************************************************************
 * Project: BaBar detector at the SLAC PEP-II B-factory
 * Package: EvtGenModels
 *    File: $Id: EvtD0mixDalitz.hh,v 1.6 2008/11/14 12:22:06 jordix Exp $
 *
 * Description:
 *   The D0mixDalitz model, with many resonances and mixing implemented.
 *
 * Modification history:
 *   Jordi Garra Ticó     2008/07/03         File created
 *****************************************************************************/

#ifndef __EVTD0MIXDALITZ_HH__
#define __EVTD0MIXDALITZ_HH__

#include "EvtGenBase/EvtComplex.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtId.hh"
#include "EvtGenBase/EvtDecayAmp.hh"
#include "EvtGenBase/EvtDalitzPoint.hh"
#include "EvtGenBase/EvtSpinType.hh"
#include "EvtGenBase/EvtDalitzReso.hh"
#include "EvtGenBase/EvtCyclic3.hh"


class EvtD0mixDalitz : public EvtDecayAmp
{
private:
  int _d1;
  int _d2;
  int _d3;

  // Mixing parameters.
  double _x;
  double _y;

  // q/p CP violation in the mixing.
  EvtComplex _qp;

  // Checker of the decay mode.
  bool _isKsPiPi;
  bool _isRBWmodel;

  // Useful constants.
  static const EvtSpinType::spintype& _SCALAR;
  static const EvtSpinType::spintype& _VECTOR;
  static const EvtSpinType::spintype& _TENSOR;

  static const EvtDalitzReso::CouplingType& _EtaPic;
  static const EvtDalitzReso::CouplingType& _PicPicKK;

  static const EvtDalitzReso::NumType& _RBW;
  static const EvtDalitzReso::NumType& _GS;
  static const EvtDalitzReso::NumType& _KMAT;

  static const EvtCyclic3::Pair& _AB;
  static const EvtCyclic3::Pair& _AC;
  static const EvtCyclic3::Pair& _BC;

  // Values to be read or computed based on values in the evt.pdl file.
  // IDs of the relevant particles.
  EvtId _D0;
  EvtId _D0B;
  EvtId _KM;
  EvtId _KP;
  EvtId _K0;
  EvtId _K0B;
  EvtId _KL;
  EvtId _KS;
  EvtId _PIM;
  EvtId _PIP;

  // Masses of the relevant particles.
  double _mD0;
  double _mKs;
  double _mPi;
  double _mK;

  // Life time and decay rate.
  double _ctau;
  double _gamma;

  // Some useful integrals over the Dalitz plot.
  EvtComplex _iChi;
  EvtComplex _iChi2;

  void readPDGValues();
  EvtComplex dalitzKsPiPi( const EvtDalitzPoint& point );
  EvtComplex dalitzKsKK  ( const EvtDalitzPoint& point );

  // Time evolution functions for hamiltonian eigenstates.
  //    Negative exponential part removed.
  EvtComplex h1( const double& ct ) const;
  EvtComplex h2( const double& ct ) const;

  void reportInvalidAndExit() const
  {
    report( ERROR, "EvtD0mixDalitz" ) << "EvtD0mixDalitz: Invalid mode." << std::endl;
    exit( 1 );
  }
public:
  EvtD0mixDalitz() : _d1( 0 ), _d2( 0 ), _d3( 0 ),
		     _x( 0. ), _y( 0. ), _qp( 1. ),
		     _isKsPiPi( false ), _isRBWmodel( true )
  {}

  virtual ~EvtD0mixDalitz() {};

  // One-line inline functions.
  std::string   getName() { return "D0MIXDALITZ";      }
  EvtDecayBase* clone()   { return new EvtD0mixDalitz; }
  void initProbMax()      { setProbMax( 5200. );       }

  void init();
  void decay( EvtParticle* p );
};

#endif