EvtSTS.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: EvtSTS.cc
//
// Description: Routine to decay scalar -> tensor scalar.
//
//
// Modification history:
//
//    RYD       Aug  21, 1998       Module created
//
//------------------------------------------------------------------------
// 
#include "EvtGenBase/EvtPatches.hh"
#include <stdlib.h>
#include "EvtGenBase/EvtParticle.hh"
#include "EvtGenBase/EvtGenKine.hh"
#include "EvtGenBase/EvtCPUtil.hh"
#include "EvtGenBase/EvtTensor4C.hh"
#include "EvtGenBase/EvtVector4C.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtReport.hh"
#include "EvtGenModels/EvtSTS.hh"
#include "EvtGenBase/EvtId.hh"
#include <string>
 
EvtSTS::~EvtSTS() {}
 
void EvtSTS::getName(std::string& model_name){
 
  model_name="STS";     
 
}
 
 
EvtDecayBase* EvtSTS::clone(){
 
  return new EvtSTS;
 
}
 
void EvtSTS::initProbMax(){
 
  setProbMax(20.0);
 
}
 
void EvtSTS::init(){
 
  // check that there are 0 arguments
  checkNArg(0);
  checkNDaug(2);
    
  checkSpinParent(EvtSpinType::SCALAR);
 
  checkSpinDaughter(0,EvtSpinType::TENSOR);
  checkSpinDaughter(1,EvtSpinType::SCALAR);
 
}
 
 
void EvtSTS::decay( EvtParticle *p){
 
  p->initializePhaseSpace(getNDaug(),getDaugs());
 
  EvtParticle* t1=p->getDaug(0);
 
  EvtVector4R momt = t1->getP4();
  EvtVector4R moms = p->getDaug(1)->getP4();
  double masst = t1->mass();
 
  EvtVector4R p4_parent=momt+moms;
 
  double m_parent=p4_parent.mass();
 
  double norm=masst*masst/(m_parent*momt.d3mag()*momt.d3mag());
   
  vertex(0,norm*t1->epsTensorParent(0).cont1(p4_parent)*p4_parent);
  vertex(1,norm*t1->epsTensorParent(1).cont1(p4_parent)*p4_parent);
  vertex(2,norm*t1->epsTensorParent(2).cont1(p4_parent)*p4_parent);
  vertex(3,norm*t1->epsTensorParent(3).cont1(p4_parent)*p4_parent);
  vertex(4,norm*t1->epsTensorParent(4).cont1(p4_parent)*p4_parent);
 
  return ;
}