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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
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/Beam.hh"
  4#include "Rivet/Projections/ChargedFinalState.hh"
  5
  6#define I_KNOW_THE_INITIAL_QUARKS_PROJECTION_IS_DODGY_BUT_NEED_TO_USE_IT
  7#include "Rivet/Projections/InitialQuarks.hh"
  8
  9namespace Rivet {
 10
 11
 12  /// @brief charged multiplicity at 58 GeV
 13  class VENUS_1998_I453613 : public Analysis {
 14  public:
 15
 16    /// Constructor
 17    RIVET_DEFAULT_ANALYSIS_CTOR(VENUS_1998_I453613);
 18
 19
 20    /// @name Analysis methods
 21    /// @{
 22
 23    /// Book histograms and initialise projections before the run
 24    void init() {
 25      declare(Beam(), "Beams");
 26      declare(ChargedFinalState(), "CFS");
 27      declare(InitialQuarks(), "IQF");
 28      book(_cLight , "/TMP/CLIGHT" );
 29      book(_cBottom, "/TMP/CBOTTOM");
 30      book(_weightLight , "/TMP/WLIGHT" );
 31      book(_weightBottom, "/TMP/WBOTTOM");
 32    }
 33
 34
 35    /// Perform the per-event analysis
 36    void analyze(const Event& event) {
 37      // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
 38      const FinalState& cfs = apply<FinalState>(event, "CFS");
 39      if (cfs.size() < 2) vetoEvent;
 40
 41
 42      int flavour = 0;
 43      const InitialQuarks& iqf = apply<InitialQuarks>(event, "IQF");
 44
 45      // If we only have two quarks (qqbar), just take the flavour.
 46      // If we have more than two quarks, look for the highest energetic q-qbar pair.
 47      if (iqf.particles().size() == 2) {
 48        flavour = iqf.particles().front().abspid();
 49      }
 50      else {
 51        map<int, double> quarkmap;
 52        for ( const Particle& p : iqf.particles()) {
 53          if (quarkmap[p.pid()] < p.E()) {
 54            quarkmap[p.pid()] = p.E();
 55          }
 56        }
 57        double maxenergy = 0.;
 58        for (int i = 1; i <= 5; ++i) {
 59          if (quarkmap[i]+quarkmap[-i] > maxenergy) {
 60            flavour = i;
 61          }
 62        }
 63      }
 64      const size_t numParticles = cfs.particles().size();
 65      switch (flavour) {
 66      case 1: case 2: case 3:
 67        _weightLight->fill();
 68        _cLight->fill(numParticles);
 69        break;
 70      case 5:
 71        _weightBottom->fill();
 72        _cBottom->fill(numParticles);
 73        break;
 74      }
 75
 76    }
 77
 78
 79    /// Normalise histograms etc., after the run
 80    void finalize() {
 81      // calculate the averages and diffs
 82      if(_weightLight ->effNumEntries()!=0) scale( _cLight, 1./ *_weightLight);
 83      if(_weightBottom->effNumEntries()!=0) scale(_cBottom, 1./ *_weightBottom);
 84      Counter _cDiff = *_cBottom - *_cLight;
 85      // fill the histograms
 86      for (unsigned int ix=1;ix<4;++ix) {
 87        double val(0.), err(0.0);
 88        if (ix==1) {
 89          val = _cBottom->val();
 90          err = _cBottom->err();
 91        }
 92        else if (ix==2) {
 93          val = _cLight->val();
 94          err = _cLight->err();
 95        }
 96        else if (ix==3) {
 97          val = _cDiff.val();
 98          err = _cDiff.err();
 99        }
100        Estimate1DPtr mult;
101        book(mult,1, 1, ix);
102        for (auto& b : mult->bins()) {
103          if (inRange(sqrtS()/GeV, b.xMin(), b.xMax())) {
104            b.set(val, err);
105          }
106        }
107      }
108
109    }
110
111    /// @}
112
113    /// @name Multiplicities
114    /// @{
115    CounterPtr _cLight;
116    CounterPtr _cCharm;
117    CounterPtr _cBottom;
118    /// @}
119
120    /// @name Weights
121    /// @{
122    CounterPtr _weightLight;
123    CounterPtr _weightBottom;
124    /// @}
125
126  };
127
128
129  RIVET_DECLARE_PLUGIN(VENUS_1998_I453613);
130
131
132}