EvtSVSCP.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: EvtSVSCP.cc
//
// Description: Routine to decay scalar -> vectors scalar
//              and has CP violation.
//
// Modification history:
//
//    RYD       Febuary 10, 1997       Module created
//
//------------------------------------------------------------------------
// 
#include "EvtGenBase/EvtPatches.hh"
#include <stdlib.h>
#include "EvtGenBase/EvtParticle.hh"
#include "EvtGenBase/EvtGenKine.hh"
#include "EvtGenBase/EvtCPUtil.hh"
#include "EvtGenBase/EvtVector4C.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtReport.hh"
#include "EvtGenModels/EvtSVSCP.hh"
#include <string>
#include "EvtGenBase/EvtConst.hh"
 
EvtSVSCP::~EvtSVSCP() {}
 
void EvtSVSCP::getName(std::string& model_name){
 
  model_name="SVS_CP";     
 
}
 
 
EvtDecayBase* EvtSVSCP::clone(){
 
  return new EvtSVSCP;
 
}
 
void EvtSVSCP::init(){
 
  // check that there are 7 arguments
  checkNArg(7);
  checkNDaug(2);
 
  checkSpinParent(EvtSpinType::SCALAR);
 
  checkSpinDaughter(0,EvtSpinType::VECTOR);
  checkSpinDaughter(1,EvtSpinType::SCALAR);
 
 
}
 
 
void EvtSVSCP::initProbMax(){
 
  //This is probably not quite right, but it should do as a start...
  //Anders
 
  setProbMax(2*(getArg(3)*getArg(3)+getArg(5)*getArg(5)));
 
}
 
 
void EvtSVSCP::decay( EvtParticle *p ){
 
  //added by Lange Jan4,2000
  static EvtId B0=EvtPDL::getId("B0");
  static EvtId B0B=EvtPDL::getId("anti-B0");
 
  EvtParticle *v;
  p->initializePhaseSpace(getNDaug(),getDaugs());
  v = p->getDaug(0);
  EvtVector4R momv = v->getP4();
  EvtVector4R moms = p->getDaug(1)->getP4();
  double massv = v->mass();
  double t;
  EvtId other_b;
 
  EvtCPUtil::OtherB(p,t,other_b);
 
  EvtComplex amp;
 
  EvtComplex A,Abar;
 
  A=EvtComplex(getArg(3)*cos(getArg(4)),getArg(3)*sin(getArg(4)));
  Abar=EvtComplex(getArg(5)*cos(getArg(6)),getArg(5)*sin(getArg(6)));
   
  if (other_b==B0B){
    amp=A*cos(getArg(1)*t/(2*EvtConst::c))+
      EvtComplex(cos(-2.0*getArg(0)),sin(-2.0*getArg(0)))*
      getArg(2)*EvtComplex(0.0,1.0)*Abar*sin(getArg(1)*t/(2*EvtConst::c));
  }
  if (other_b==B0){
    amp=A*EvtComplex(cos(2.0*getArg(0)),sin(2.0*getArg(0)))*
      EvtComplex(0.0,1.0)*sin(getArg(1)*t/(2*EvtConst::c))+       
      getArg(2)*Abar*cos(getArg(1)*t/(2*EvtConst::c));
  }
  
  EvtVector4R p4_parent;
  
  p4_parent=momv+moms;
  
  double norm=massv/(momv.d3mag()*p4_parent.mass());
  
  vertex(0,amp*norm*p4_parent*(v->epsParent(0)));
  vertex(1,amp*norm*p4_parent*(v->epsParent(1)));
  vertex(2,amp*norm*p4_parent*(v->epsParent(2)));
  
  return ;
}