BesEvtGen-00-04-08/src/EvtGen/EvtGenBase/EvtTwoBodyKine.hh

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/*******************************************************************************
 * Project: BaBar detector at the SLAC PEP-II B-factory
 * Package: EvtGenBase
 *    File: $Id: EvtTwoBodyKine.hh,v 1.1.1.2 2007/10/26 05:03:14 pingrg Exp $
 *  Author: Alexei Dvoretskii, [email protected], 2001-2002
 *
 * Copyright (C) 2002 Caltech
 *******************************************************************************/
 
// Descriptions of the kinematics of a two-body decay.
 
#ifndef EVT_TWO_BODY_KINE_HH
#define EVT_TWO_BODY_KINE_HH
 
#include <iostream>
 
class EvtTwoBodyKine {
 
public:
  
  enum Index {A,B,AB}; 
 
  EvtTwoBodyKine();
  EvtTwoBodyKine(double mA, double mB, double mAB);
  EvtTwoBodyKine(const EvtTwoBodyKine& other);
  ~EvtTwoBodyKine();
 
  // Accessors
 
  inline double mA()  const { return _mA; }
  inline double mB()  const { return _mB; }
  inline double mAB() const { return _mAB; } 
  double m(Index i) const;
 
  // Momentum of the other two particles in the 
  // rest-frame of particle i.
 
  double p(Index i = AB) const;
 
  // Energy of particle i in the rest frame of particle j
 
  double e(Index i, Index j) const;
 
  void print(std::ostream& os) const;
  
private:
  
  double _mA;
  double _mB;
  double _mAB;
};
 
std::ostream& operator<<(std::ostream& os, const EvtTwoBodyKine& p);
 
#endif