EvtJscont.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: EvtJscont.cc
//
// Description: Routine to generate e+e- --> q\barq  via Jetset
//
// Modification history:
//
//    PCK     August 4, 1997        Module created
//
//------------------------------------------------------------------------
//
#include "EvtJscont.hh"
#include "../EvtGenBase/EvtDecayTable.hh"
#include "../EvtGenBase/EvtId.hh"
#include "../EvtGenBase/EvtPDL.hh"
#include "../EvtGenBase/EvtParticle.hh"
#include "../EvtGenBase/EvtPatches.hh"
#include "../EvtGenBase/EvtReport.hh"
#include "EvtJetSet.hh"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string>
#include <strstream>
using std::strstream;
 
extern "C" {
extern void continuum_( double*, int*, int*, int*, double*, double*, double*, double* );
}
 
extern "C" {
extern void lugive_( const char* cnfgstr, int length );
}
 
EvtJscont::~EvtJscont() {}
 
void EvtJscont::getName( std::string& model_name ) { model_name = "JSCONT"; }
 
EvtDecayBase* EvtJscont::clone() { return new EvtJscont; }
 
void EvtJscont::init() {
 
  // check that there are 1 argument
 
  checkNArg( 1, 2 );
}
 
void EvtJscont::initProbMax() { noProbMax(); }
 
void EvtJscont::decay( EvtParticle* p ) {
 
  EvtJetSet::jetSetInit();
  static int first = 1;
 
  if ( first )
  {
    first = 0;
 
    float val = 0.6;
    if ( getNArg() > 1 ) { val = getArg( 1 ); }
    char vak[20];
    sprintf( vak, "PARJ(13)=%f", val );
    std::string temp( vak );
    lugive_( temp.c_str(), strlen( temp.c_str() ) );
  }
  EvtVector4R p4[100];
 
  double energy = p->mass();
 
  int flavor;
 
  int   i, more;
  int   ndaugjs;
  int   kf[100];
  EvtId id[100];
  int   type[MAX_DAUG];
 
  flavor = (int)getArg( 0 );
 
  double px[100], py[100], pz[100], e[100];
 
  if ( p->getNDaug() != 0 ) { return; }
  do {
 
    continuum_( &energy, &flavor, &ndaugjs, kf, px, py, pz, e );
 
    for ( i = 0; i < ndaugjs; i++ )
    {
 
      id[i] = EvtPDL::evtIdFromStdHep( kf[i] );
 
      type[i] = EvtPDL::getSpinType( id[i] );
 
      // have to protect against negative mass^2 for massless particles
      // i.e. neutrinos and photons.
      // this is uggly but I need to fix it right now....
 
      if ( px[i] * px[i] + py[i] * py[i] + pz[i] * pz[i] >= e[i] * e[i] )
      { e[i] = sqrt( px[i] * px[i] + py[i] * py[i] + pz[i] * pz[i] ) + 0.0000000000001; }
 
      p4[i].set( e[i], px[i], py[i], pz[i] );
    }
 
    int channel = EvtDecayTable::inChannelList( p->getId(), ndaugjs, id );
 
    more = ( ( channel != -1 ) && ( channel != p->getChannel() ) );
 
  } while ( more );
 
  p->makeDaughters( ndaugjs, id );
 
  for ( i = 0; i < ndaugjs; i++ ) { p->getDaug( i )->init( id[i], p4[i] ); }
  return;
}