EvtSinglePoint.cc

Go to the documentation of this file.

//--------------------------------------------------------------------------
//
//
// Module: EvtSinglePoint.cc
//
// Description: Special model to generate single particles with fixed momentu.
//
// Modification history:
//
//    RYD       Febuary 17,1998       Module created
//
//------------------------------------------------------------------------
//
#include "EvtSinglePoint.hh"
#include "../EvtGenBase/EvtConst.hh"
#include "../EvtGenBase/EvtPDL.hh"
#include "../EvtGenBase/EvtParticle.hh"
#include "../EvtGenBase/EvtPatches.hh"
#include "../EvtGenBase/EvtRandom.hh"
#include "../EvtGenBase/EvtReport.hh"
#include <stdlib.h>
#include <string>
using std::endl;
 
EvtSinglePoint::~EvtSinglePoint() {}
 
void EvtSinglePoint::getName( std::string& model_name ) { model_name = "SinglePoint"; }
 
EvtDecayBase* EvtSinglePoint::clone() { return new EvtSinglePoint(); }
 
void EvtSinglePoint::init() {
 
  // turn off checks for charge conservation
  disableCheckQ();
 
  if ( ( getNArg() == 3 ) )
  {
    px = getArg( 0 );
    py = getArg( 1 );
    pz = getArg( 2 );
  }
  else
  {
    std::cout << "expected three parameters: px, py, pz, but find " << getNArg()
              << " parameters" << std::endl;
    ::abort();
  }
}
 
void EvtSinglePoint::decay( EvtParticle* p ) {
 
  EvtParticle* d;
  EvtVector4R  p4;
 
  double mass = EvtPDL::getMass( getDaug( 0 ) );
 
  p->makeDaughters( getNDaug(), getDaugs() );
  d = p->getDaug( 0 );
 
  // generate flat distribution in p
  // we are now in the parents restframe! This means the
  // restframe of the e+e- collison.
 
  double pmag;
  pmag = sqrt( px * px + py * py + py * pz );
 
  p4.set( sqrt( mass * mass + pmag * pmag ), px, py, pz );
  d->init( getDaug( 0 ), p4 );
  return;
}