EvtSSSCPT.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: EvtSSSCPT.cc
//
// Description: Routine to decay scalar -> 2 scalars (CPT)
//
// Modification history:
//
//    SHY       April 28, 1997       Module created
//
//------------------------------------------------------------------------
//
#include "EvtSSSCPT.hh"
#include "../EvtGenBase/EvtCPUtil.hh"
#include "../EvtGenBase/EvtConst.hh"
#include "../EvtGenBase/EvtGenKine.hh"
#include "../EvtGenBase/EvtId.hh"
#include "../EvtGenBase/EvtPDL.hh"
#include "../EvtGenBase/EvtParticle.hh"
#include "../EvtGenBase/EvtPatches.hh"
#include "../EvtGenBase/EvtReport.hh"
#include <stdlib.h>
#include <string>
 
EvtSSSCPT::~EvtSSSCPT() {}
 
void EvtSSSCPT::getName( std::string& model_name ) { model_name = "SSS_CPT"; }
 
EvtDecayBase* EvtSSSCPT::clone() { return new EvtSSSCPT; }
 
void EvtSSSCPT::init() {
 
  // check that there are 8 arguments
  checkNArg( 8 );
  checkNDaug( 2 );
}
 
void EvtSSSCPT::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;
 
  EvtCPUtil::OtherB( p, t, other_b );
 
  p->initializePhaseSpace( getNDaug(), getDaugs() );
 
  EvtComplex amp;
 
  EvtComplex A, Abar;
  EvtComplex P, Q, D, Im;
 
  P  = EvtComplex( cos( -getArg( 0 ) ), sin( -getArg( 0 ) ) );
  Q  = EvtComplex( cos( getArg( 0 ) ), sin( getArg( 0 ) ) );
  D  = EvtComplex( getArg( 6 ) * cos( getArg( 7 ) ), getArg( 6 ) * sin( getArg( 7 ) ) );
  Im = EvtComplex( 0.0, 1.0 );
 
  A    = EvtComplex( getArg( 2 ) * cos( getArg( 3 ) ), getArg( 2 ) * sin( getArg( 3 ) ) );
  Abar = EvtComplex( getArg( 4 ) * cos( getArg( 5 ) ), getArg( 4 ) * sin( getArg( 5 ) ) );
 
  if ( other_b == B0B )
  {
    amp = A * cos( getArg( 1 ) * t / ( 2 * EvtConst::c ) ) +
          Im * sin( getArg( 1 ) * t / ( 2 * EvtConst::c ) ) * ( Q / P * A + 2.0 * D * Abar );
  }
  if ( other_b == B0 )
  {
    amp = Abar * cos( getArg( 1 ) * t / ( 2 * EvtConst::c ) ) +
          Im * sin( getArg( 1 ) * t / ( 2 * EvtConst::c ) ) * ( P / Q * A - 2.0 * D * Abar );
  }
 
  vertex( amp );
 
  return;
}