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VENUS_1998_I453613

Charged particle multiplicities in heavy and light quark initiated events at 58 GeV
Experiment: VENUS (Tristan)
Inspire ID: 453613
Status: VALIDATED
No authors listed References:
  • Phys.Lett. B423 (1998) 407-418
Beams: e+ e-
Beam energies: (29.0, 29.0) GeV
Run details:
  • e+e- > hadrons

Measurement of the mean charged multiplicities separately for $b\bar b$, and light quark ($uds$) initiated events in $e^+e^-$ interactions at 58 GeV.

Source code: VENUS_1998_I453613.cc
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// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/ChargedFinalState.hh"

#define I_KNOW_THE_INITIAL_QUARKS_PROJECTION_IS_DODGY_BUT_NEED_TO_USE_IT
#include "Rivet/Projections/InitialQuarks.hh"

namespace Rivet {


  /// @brief charged multiplicity at 58 GeV
  class VENUS_1998_I453613 : public Analysis {
  public:

    /// Constructor
    DEFAULT_RIVET_ANALYSIS_CTOR(VENUS_1998_I453613);


    /// @name Analysis methods
    //@{

    /// Book histograms and initialise projections before the run
    void init() {
      declare(Beam(), "Beams");
      declare(ChargedFinalState(), "CFS");
      declare(InitialQuarks(), "IQF");
      book(_cLight , "/TMP/CLIGHT" );
      book(_cBottom, "/TMP/CBOTTOM");
      book(_weightLight , "/TMP/WLIGHT" );
      book(_weightBottom, "/TMP/WBOTTOM");
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
      const FinalState& cfs = apply<FinalState>(event, "CFS");
      if (cfs.size() < 2) vetoEvent;


      int flavour = 0;
      const InitialQuarks& iqf = apply<InitialQuarks>(event, "IQF");

      // If we only have two quarks (qqbar), just take the flavour.
      // If we have more than two quarks, look for the highest energetic q-qbar pair.
      if (iqf.particles().size() == 2) {
        flavour = iqf.particles().front().abspid();
      }
      else {
        map<int, double> quarkmap;
        for ( const Particle& p : iqf.particles()) {
          if (quarkmap[p.pid()] < p.E()) {
            quarkmap[p.pid()] = p.E();
          }
        }
        double maxenergy = 0.;
        for (int i = 1; i <= 5; ++i) {
          if (quarkmap[i]+quarkmap[-i] > maxenergy) {
            flavour = i;
          }
        }
      }
      const size_t numParticles = cfs.particles().size();
      switch (flavour) {
      case 1: case 2: case 3:
	_weightLight->fill();  ;
        _cLight->fill(numParticles);
        break;
      case 5:
        _weightBottom->fill();
        _cBottom->fill(numParticles);
        break;
      }

    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // calculate the averages and diffs
      if(_weightLight ->effNumEntries()!=0) scale( _cLight, 1./ *_weightLight);
      if(_weightBottom->effNumEntries()!=0) scale(_cBottom, 1./ *_weightBottom);
      Counter _cDiff = *_cBottom - *_cLight;
      // fill the histograms
      for(unsigned int ix=1;ix<4;++ix) {
	double val(0.), err(0.0);
	if(ix==1) {
	  val = _cBottom->val();
	  err = _cBottom->err();
	}
	else if(ix==2) {
	  val = _cLight->val();
	  err = _cLight->err();
	}
	else if(ix==3) {
	  val = _cDiff.val();
	  err = _cDiff.err();
	}
	Scatter2D temphisto(refData(1, 1, ix));
	Scatter2DPtr mult;
	book(mult,1, 1, ix);
	for (size_t b = 0; b < temphisto.numPoints(); b++) {
	  const double x  = temphisto.point(b).x();
	  pair<double,double> ex = temphisto.point(b).xErrs();
	  pair<double,double> ex2 = ex;
	  if(ex2.first ==0.) ex2. first=0.0001;
	  if(ex2.second==0.) ex2.second=0.0001;
	  if (inRange(sqrtS()/GeV, x-ex2.first, x+ex2.second)) {
	    mult->addPoint(x, val, ex, make_pair(err,err));
	  }
	  else {
	    mult->addPoint(x, 0., ex, make_pair(0.,.0));
	  }
	}
      }

    }

    //@}

    /// @name Multiplicities
    //@{
    CounterPtr _cLight;
    CounterPtr _cCharm;
    CounterPtr _cBottom;
    //@}

    /// @name Weights
    //@{
    CounterPtr _weightLight;
    CounterPtr _weightBottom;
    //@}

  };


  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(VENUS_1998_I453613);


}