BesEvtGen-00-04-08/src/EvtGen/EvtGenModels/EvtVSS.cc

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//--------------------------------------------------------------------------
//
// 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: See EvtGen/COPYRIGHT
//      Copyright (C) 1998      Caltech, UCSB
//
// Module: EvtVSS.cc
//
// Description: Routine to decay vector-> scalar scalar
//
// Modification history:
//
//    RYD       November 24, 1996       Module created
//
//------------------------------------------------------------------------
// 
#include "EvtGenBase/EvtPatches.hh"
#include <stdlib.h>
#include "EvtGenBase/EvtParticle.hh"
#include "EvtGenBase/EvtGenKine.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtVector4C.hh"
#include "EvtGenBase/EvtVector4R.hh"
#include "EvtGenBase/EvtReport.hh"
#include "EvtGenModels/EvtVSS.hh"
#include <string>
 
EvtVSS::~EvtVSS() {}
 
void EvtVSS::getName(std::string& model_name){
 
  model_name="VSS"; 
    
}
 
 
EvtDecayBase* EvtVSS::clone(){
 
  return new EvtVSS;
 
}
 
void EvtVSS::init(){
 
  // check that there are 0 arguments
  checkNArg(0);
 
  // check that there are 2 daughters
  checkNDaug(2);
 
  // check the parent and daughter spins
  checkSpinParent(EvtSpinType::VECTOR);
  checkSpinDaughter(0,EvtSpinType::SCALAR);
  checkSpinDaughter(1,EvtSpinType::SCALAR);
}
 
void EvtVSS::initProbMax() {
 
   setProbMax(1.0);
 
}      
 
void EvtVSS::decay( EvtParticle *p){
 
  p->initializePhaseSpace(getNDaug(),getDaugs());
 
  EvtVector4R pDaug = p->getDaug(0)->getP4();
  
  double norm=1.0/pDaug.d3mag();
 
  for (int i=0; i<3; i++) vertex(i,norm*pDaug*(p->eps(i)));
 
  return;
}