EvtPBB1.cc

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//--------------------------------------------------------------------------
//
// Environment:
//      This software is part of models developed at BES collaboration
//      based on the EvtGen framework.  If you use all or part
//      of it, please give an appropriate acknowledgement.
//
// Copyright Information: See EvtGen/BesCopyright
//      Copyright (A) 2006      Ping Rong-Gang, Pang Cai-Ying@IHEP
//
//
// Module: EvtPBB1.cc
//
// Description: Routine to decay Pseudoscalar-> B_8 bar B_8 using helicity amplitude.
//
// Modification history:
//
//    Ping R.-G.    Apr., 2006       Module created
//
//------------------------------------------------------------------------
//
#include "EvtPBB1.hh"
#include "../EvtGenBase/EvtGenKine.hh"
#include "../EvtGenBase/EvtHelSys.hh"
#include "../EvtGenBase/EvtPDL.hh"
#include "../EvtGenBase/EvtParticle.hh"
#include "../EvtGenBase/EvtPatches.hh"
#include "../EvtGenBase/EvtReport.hh"
#include "../EvtGenBase/EvtTensor4C.hh"
#include "../EvtGenBase/EvtVector4C.hh"
#include "../EvtGenBase/EvtVector4R.hh"
#include "../EvtGenBase/EvtdFunction.hh"
#include <stdlib.h>
#include <string>
using std::endl;
 
EvtPBB1::~EvtPBB1() {}
 
void EvtPBB1::getName( std::string& model_name ) { model_name = "PBB1"; }
 
EvtDecayBase* EvtPBB1::clone() { return new EvtPBB1; }
 
void EvtPBB1::initProbMax() {
  double ProbMax = 2.;
  setProbMax( ProbMax );
}
 
void EvtPBB1::init() {
  checkNDaug( 2 );
  checkSpinParent( EvtSpinType::SCALAR );
  checkSpinDaughter( 0, EvtSpinType::DIRAC );
  checkSpinDaughter( 1, EvtSpinType::DIRAC );
}
 
void EvtPBB1::decay( EvtParticle* p ) {
 
  p->initializePhaseSpace( getNDaug(), getDaugs() );
 
  double phs = getArg( 0 );
 
  vertex( 0, 0, exp( EvtComplex( 0, phs ) ) );
  vertex( 0, 1, 0.0 );
  vertex( 1, 0, 0.0 );
  vertex( 1, 1, -exp( EvtComplex( 0, phs ) ) );
 
  return;
}