EvtSVSNONCPEIGEN.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: EvtSVSNONCPEIGEN.cc
//
// Description: Routine to decay scalar -> vectors scalar
//              and has CP violation.
//
// Modification history:
//
//    RYD       April 26, 1997       Module created
//
//------------------------------------------------------------------------
// 
#include "EvtGenBase/EvtPatches.hh"
#include <stdlib.h>
#include "EvtGenBase/EvtParticle.hh"
#include "EvtGenBase/EvtRandom.hh"
#include "EvtGenBase/EvtGenKine.hh"
#include "EvtGenBase/EvtCPUtil.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtReport.hh"
#include "EvtGenBase/EvtVector4C.hh"
#include "EvtGenModels/EvtSVSNONCPEIGEN.hh"
#include <string>
#include "EvtGenBase/EvtConst.hh"
 
EvtSVSNONCPEIGEN::~EvtSVSNONCPEIGEN() {}
 
void EvtSVSNONCPEIGEN::getName(std::string& model_name){
 
  model_name="SVS_NONCPEIGEN";     
 
}
 
 
EvtDecayBase* EvtSVSNONCPEIGEN::clone(){
 
  return new EvtSVSNONCPEIGEN;
 
}
 
void EvtSVSNONCPEIGEN::init(){
 
  // check that there are 11 arguments
  checkNArg(11,7);
  checkNDaug(2);
 
  checkSpinDaughter(0,EvtSpinType::VECTOR);
  checkSpinDaughter(1,EvtSpinType::SCALAR);
 
  _dm=getArg(1);
  _phickm=2*getArg(0)+getArg(2);
 
  _A_f=EvtComplex(getArg(3)*cos(getArg(4)),getArg(3)*sin(getArg(4)));
  _Abar_f=EvtComplex(getArg(5)*cos(getArg(6)),getArg(5)*sin(getArg(6)));
  
  _A_fbar=_Abar_f;
  _Abar_fbar=_A_f;
 
  if (getNArg()==11){
    _A_fbar=EvtComplex(getArg(7)*cos(getArg(8)),getArg(7)*sin(getArg(8)));
    _Abar_fbar=EvtComplex(getArg(9)*cos(getArg(10)),getArg(9)*sin(getArg(10)));
  }
}
 
void EvtSVSNONCPEIGEN::initProbMax() {
  double theProbMax = 
    abs(_A_f) * abs(_A_f) +
    abs(_Abar_f) * abs(_Abar_f) +
    abs(_A_fbar) * abs(_A_fbar) +
    abs(_Abar_fbar) * abs(_Abar_fbar);
  
  setProbMax(theProbMax);
}
 
void EvtSVSNONCPEIGEN::decay( EvtParticle *p){
 
  //added by Lange Jan4,2000
  static EvtId B0=EvtPDL::getId("B0");
  static EvtId B0B=EvtPDL::getId("anti-B0");
 
  double t;
  EvtId other_b;
  EvtId daugs[2];
 
  // MB: flip selects the final of the decay
  int flip = ((p->getId() == B0) ? 0 : 1);
  daugs[0]=getDaug(0);
  daugs[1]=getDaug(1);
  p->initializePhaseSpace(2, daugs);
 
  EvtCPUtil::OtherB(p,t,other_b,0.5);
 
  EvtComplex amp;
  double dmt2 = (_dm * t) / (2 * EvtConst::c);
  EvtComplex ePlusIPhi(cos(_phickm), sin(_phickm));
  EvtComplex eMinusIPhi(cos(-_phickm), -sin(_phickm));
 
  // flip == 0 : D-rho+
  // flip == 1 : D+rho-
 
   if (!flip) {
     if (other_b==B0B){
       // At t=0 we have a B0
       amp = cos(dmt2)*_A_f + eMinusIPhi*EvtComplex(0.0,sin(dmt2))*_Abar_f;
     }
     if (other_b==B0){
       // At t=0 we have a B0bar
       amp = ePlusIPhi*EvtComplex(0.0,sin(dmt2))*_A_f + cos(dmt2)*_Abar_f;
     }
   }
   else{
     if (other_b==B0B){
       // At t=0 we have a B0
       amp = cos(dmt2)*_A_fbar + eMinusIPhi*EvtComplex(0.0,sin(dmt2))*_Abar_fbar;
     }
     if (other_b==B0){
       // At t=0 we have a B0bar
       amp = ePlusIPhi*EvtComplex(0.0,sin(dmt2))*_A_fbar + cos(dmt2)*_Abar_fbar;
     }
   }
 
 
  EvtParticle *v;
  v= p->getDaug(0);
 
  EvtVector4R momv = p->getDaug(0)->getP4();
  EvtVector4R moms = p->getDaug(1)->getP4();
  EvtVector4R p4_parent=momv+moms;
 
  double norm=momv.mass()/(momv.d3mag()*p->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 ;
}