EvtVVS.hh

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//--------------------------------------------------------------------------
//
// Environment:
//      This software is part of models developed at BES collaboration
//      based on the EvtGen framework.  If you use all or part
//      of it, please give an appropriate acknowledgement.
//
// Copyright Information: See EvtGen/BesCopyright
//      Copyright (A) 2006      Ping Rong-Gang @IHEP
//
// Module: VVS.hh
//
// Description: To define the helicity for vector(s=+1,-1)->vector(s=-1,0,1)+Pseudoscalar
//
// Modification history:
//
//    Ping R.-G.       Apr., 2006       Module created
//
//------------------------------------------------------------------------
//
#include "../EvtGenBase/EvtKine.hh"
#include "../EvtGenBase/EvtParticle.hh"
#include "../EvtGenBase/EvtPatches.hh"
#include <math.h>
#include <stdlib.h>
 
#include "../EvtGenBase/EvtHelSys.hh"
#include "../EvtGenBase/EvtTensor4C.hh"
#include "../EvtGenBase/EvtVector4C.hh"
#include "../EvtGenBase/EvtVector4R.hh"
#include <string>
using namespace std;
 
class VVS {
public:
  VVS( EvtVector4R pd1, EvtVector4R pd2, EvtVector4R pd3, double ResonanceMass,
       double ResonanceWidth, double r1, double r2, double phase1, double phase2 ) {
    ////////////////////////////////////////////////////////////////////////////////////
    //     For the decay 1-- -->R(1--) +Pseudoscalar-->3 Pseudoscalars
    //  pd1,pd2,pd3: four momentum vector for three daughters
    //   ResonanceMass,  ResonanceWidth : resonance parameter for intermediate state R(1--)
    //  r1,r2      : the relative coupling strength for two resonaces R R.P.T another R
    //  phase1,phase2: the relatev phase of two phases R.P.T another R
    ///////////////////////////////////////////////////////////////////////////////////////////
    _pd[0]  = pd1;
    _pd[1]  = pd2;
    _pd[2]  = pd3;
    _res[0] = ResonanceMass;
    _res[1] = ResonanceWidth;
    _par[0] = r1;
    _par[1] = phase1;
    _par[2] = r2;
    _par[3] = phase2;
  }
  double     Fij( int i, int j, double r );
  double     R00( double r );
  EvtComplex amps1( int m, int i, int j );
  double     amps();
 
private:
  EvtVector4R _pd[5];
  double      _res[5];
  double      _par[5];
};