Rivet analyses

title: DELPHI_1992_I334948

Charge multiplicity for different jet multiplicities in hadronic $Z^0$ decays

Experiment: DELPHI (LEP)

Inspire ID: 334948

Status: VALIDATED

Authors: - Peter Richardson

References: - Z.Phys. C56 (1992) 63-76, 1992

Beams: e+ e-

Beam energies: (45.6, 45.6)GeV

Run details: - $\sqrt{s} = 91.2$ GeV, $e^+ e^- -> Z^0$ production with hadronic decays only

The charged multiplicity distribution in hadron $Z^0$ decays for different numbers of final state jets.

Source code:DELPHI_1992_I334948.cc

```c++ // -- C++ --

include "Rivet/Analysis.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/FastJets.hh"

namespace Rivet {

/// @brief Charged multiplicity for different numbers of final state jets class DELPHI_1992_I334948 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(DELPHI_1992_I334948);


/// @name Analysis methods
/// @{

/// Book histograms and initialise projections before the run
void init() {

  // Initialise and register projections
  const ChargedFinalState cfs;
  declare(cfs, "FS");
  declare(FastJets(cfs, JetAlg::JADE), "Jets");

  // Book histograms
  for (unsigned int ih = 0; ih < 3; ++ih) {
    for (unsigned int iy = 0; iy < 3; ++iy) {
      book(_h_mult[ih][iy], ih + 1, 1, iy + 1);
    }
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  const FinalState& fs = apply<FinalState>(event, "FS");
  const size_t numParticles = fs.particles().size();
  // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
  if (numParticles < 2) {
    MSG_DEBUG("Failed leptonic event cut");
    vetoEvent;
  }
  MSG_DEBUG("Passed leptonic event cut");
  const FastJets& jets = apply<FastJets>(event, "Jets");
  if (jets.clusterSeq()) {
    vector<double> ycut = {0.01, 0.02, 0.04};
    for (unsigned int ih = 0; ih < 3; ++ih) {
      int nbin = jets.clusterSeq()->n_exclusive_jets_ycut(ycut[ih]) - 2;
      if (nbin < 0 || nbin > 2) continue;
      _h_mult[ih][nbin]->fill(numParticles);
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {

  for (unsigned int ih = 0; ih < 3; ++ih) {
    for (unsigned int iy = 0; iy < 3; ++iy) {
      normalize(_h_mult[ih][iy], 1000.);
    }
  }
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<int> _h_mult[3][3];
/// @}

};

RIVET_DECLARE_PLUGIN(DELPHI_1992_I334948);

} ```