Rivet analyses

title: TOPAZ_1997_I454183

Measurement of charged particle multiplicity vs thrust at $E_{\text{CMS}}=57.8$ GeV

Experiment: TOPAZ (Tristan)

Inspire ID: 454183

Status: UNVALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B413 (1997) 447-452

Beams: e- e+

Beam energies: (28.9, 28.9)GeV

Run details: - e+ e- to hadrons

Measurement of the charged particle multiplicity as a function of thrust at 57.8 GeV by the TOPAZ collaboration.

Source code:TOPAZ_1997_I454183.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/Thrust.hh"

namespace Rivet {

/// @brief N charged vs thrust class TOPAZ_1997_I454183 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(TOPAZ_1997_I454183);


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

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

  // Initialise and register projections
  ChargedFinalState cfs;
  declare(cfs, "CFS");
  declare(Thrust(cfs), "Thrust");

  // Book histograms
  book(_p_charged, 3, 1, 1);
  book(_c_ncharged, 1, 1, 1);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  // First, veto on leptonic events by requiring at least 5 charged FS particles
  const ChargedFinalState& cfs = apply<ChargedFinalState>(event, "CFS");
  const size_t numParticles = cfs.particles().size();
  // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
  if (numParticles < 5) {
    MSG_DEBUG("Failed leptonic event cut");
    vetoEvent;
  }
  MSG_DEBUG("Passed leptonic event cut");

  // thrust
  const Thrust& thrust = apply<Thrust>(event, "Thrust");
  _c_ncharged->fill("57.8", cfs.particles().size());
  size_t idx = pTAxis.index(-log(1. - thrust.thrust()));
  string label = idx > 0 && idx <= _p_charged->xEdges().size() ? _p_charged->xEdges()[idx - 1] : "OTHER";
  _p_charged->fill(label, cfs.particles().size());
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_c_ncharged, 1. / sumOfWeights());
}

/// @}


/// @name Histograms
/// @{
BinnedProfilePtr<string> _p_charged;
BinnedProfilePtr<string> _c_ncharged;
YODA::Axis<double> pTAxis{1.24, 1.58, 1.9, 2.36, 2.66, 3.02, 3.24, 3.46};
/// @}

};

RIVET_DECLARE_PLUGIN(TOPAZ_1997_I454183);

} ```