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 "EvtVSS.hh"
#include "../EvtGenBase/EvtGenKine.hh"
#include "../EvtGenBase/EvtPDL.hh"
#include "../EvtGenBase/EvtParticle.hh"
#include "../EvtGenBase/EvtPatches.hh"
#include "../EvtGenBase/EvtReport.hh"
#include "../EvtGenBase/EvtVector4C.hh"
#include "../EvtGenBase/EvtVector4R.hh"
#include <stdlib.h>
#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;
}