EvtmPhsp.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: EvtmPhsp.cc
//
// Description: Routine to decay a particle according th phase space
//
// Modification history:
//
//    RYD       January 8, 1997       Module created
//
//------------------------------------------------------------------------
//
#include "EvtmPhsp.hh"
#include "../EvtGenBase/EvtGenKine.hh"
#include "../EvtGenBase/EvtPDL.hh"
#include "../EvtGenBase/EvtParticle.hh"
#include "../EvtGenBase/EvtPatches.hh"
#include "../EvtGenBase/EvtReport.hh"
#include <stdlib.h>
#include <string>
using std::endl;
 
EvtmPhsp::~EvtmPhsp() {}
 
void EvtmPhsp::getName( std::string& model_name ) { model_name = "mPHSP"; }
 
EvtDecayBase* EvtmPhsp::clone() { return new EvtmPhsp; }
 
void EvtmPhsp::init() {
 
  if ( getNArg() == 3 )
  {
    nd1 = getArg( 0 ); // assign the first nd1 particle in the son list
    ma1 = getArg( 1 ); // the lower mass for the nd1 son cluster
    ma2 = getArg( 2 ); // the upper mass for the nd1 son cluster
  }
  else if ( getNArg() == 6 )
  {
    nd1 = getArg( 0 ); // assign the first nd1 particle in the son list
    ma1 = getArg( 1 ); // the lower mass for the nd1 son cluster
    ma2 = getArg( 2 ); // the upper mass for the nd1 son cluster
    nd2 = getArg( 3 ); // assign the first nd1 particle in the son list
    mb1 = getArg( 4 ); // the lower mass for the nd2 son cluster
    mb2 = getArg( 5 ); // the upper mass for the nd2 son cluster
  }
  else
  {
 
    report( ERROR, "EvtGen" ) << "EvtmPHSP generator expected "
                              << " 3 or 6 arguments but found:" << getNArg() << endl;
    report( ERROR, "EvtGen" ) << "Will terminate execution!" << endl;
    ::abort();
  }
}
 
void EvtmPhsp::initProbMax() { noProbMax(); }
 
void EvtmPhsp::decay( EvtParticle* p ) {
  EvtVector4R pt, pt2;
loop:
 
  p->initializePhaseSpace( getNDaug(), getDaugs() );
 
  pt = p->getDaug( 0 )->getP4Lab();
  for ( int ii = 1; ii < nd1; ii++ ) { pt = pt + p->getDaug( ii )->getP4Lab(); }
  xmass1 = pt.mass();
 
  if ( getNArg() == 6 )
  {
    pt2 = p->getDaug( nd1 )->getP4Lab();
    for ( int jj = nd1 + 1; jj < nd1 + nd2; jj++ ) pt2 = pt2 + p->getDaug( jj )->getP4Lab();
  }
  xmass2 = pt2.mass();
 
  // std::cout<<"xmass1= "<<xmass1<<std::endl;
 
  if ( getNArg() == 3 && ( xmass1 < ma1 || xmass1 > ma2 ) ) goto loop;
  if ( getNArg() == 6 && ( xmass1 < ma1 || xmass1 > ma2 || xmass2 < mb1 || xmass2 > mb2 ) )
    goto loop;
 
  return;
}