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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 , 1, 1, 2);
 29      book(_cBottom, 1, 1, 1);
 30    }
 31
 32
 33    /// Perform the per-event analysis
 34    void analyze(const Event& event) {
 35      // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
 36      const FinalState& cfs = apply<FinalState>(event, "CFS");
 37      if (cfs.size() < 2) vetoEvent;
 38
 39
 40      int flavour = 0;
 41      const InitialQuarks& iqf = apply<InitialQuarks>(event, "IQF");
 42
 43      // If we only have two quarks (qqbar), just take the flavour.
 44      // If we have more than two quarks, look for the highest energetic q-qbar pair.
 45      if (iqf.particles().size() == 2) {
 46        flavour = iqf.particles().front().abspid();
 47      }
 48      else {
 49        map<int, double> quarkmap;
 50        for ( const Particle& p : iqf.particles()) {
 51          if (quarkmap[p.pid()] < p.E()) {
 52            quarkmap[p.pid()] = p.E();
 53          }
 54        }
 55        double maxenergy = 0.;
 56        for (int i = 1; i <= 5; ++i) {
 57          if (quarkmap[i]+quarkmap[-i] > maxenergy) {
 58            flavour = i;
 59          }
 60        }
 61      }
 62      const size_t numParticles = cfs.particles().size();
 63      switch (flavour) {
 64      case 1: case 2: case 3:
 65        _cLight->fill(round(sqrtS()),numParticles);
 66        break;
 67      case 5:
 68        _cBottom->fill(round(sqrtS()),numParticles);
 69        break;
 70      }
 71
 72    }
 73
 74
 75    /// Normalise histograms etc., after the run
 76    void finalize() {
 77      BinnedEstimatePtr<int> hDiff;
 78      book(hDiff,1, 1, 3);
 79      if(_cBottom->bin(1).numEntries()>0 &&
 80         _cLight ->bin(1).numEntries()>0) {
 81        double val = _cBottom->bin(1).mean(2) - _cLight->bin(1).mean(2);
 82        double err = sqrt(sqr(_cBottom->bin(1).stdErr(2)) +
 83                          sqr(_cLight ->bin(1).stdErr(2)));
 84        hDiff->bin(1).setVal(val);
 85        hDiff->bin(1).setErr(err);
 86      }
 87    }
 88
 89    /// @}
 90
 91    /// @name Multiplicities
 92    /// @{
 93    BinnedProfilePtr<int> _cLight;
 94    BinnedProfilePtr<int> _cCharm;
 95    BinnedProfilePtr<int> _cBottom;
 96    /// @}
 97
 98  };
 99
100
101  RIVET_DECLARE_PLUGIN(VENUS_1998_I453613);
102
103
104}