Rivet analyses

title: TOPAZ_1993_I361661

Measurement of event shapes at $E_{\text{CMS}}=58$ GeV

Experiment: TOPAZ (Tristan)

Inspire ID: 361661

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B304 (1993) 373-380, 1993

Beams: e- e+

Beam energies: (29.0, 29.0)GeV

Run details: - e+ e- to hadrons

Measurement of the hadronic event shapes in $e^+e^-$ collisions by TOPAZ at 58 GeV.

Source code:TOPAZ_1993_I361661.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/Hemispheres.hh"

include "Rivet/Projections/Thrust.hh"

namespace Rivet {

/// @brief Thrust, heavy jet mass, and y3 at 58 GeV class TOPAZ_1993_I361661 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(TOPAZ_1993_I361661);


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

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

  const FinalState fs;
  declare(fs, "FS");
  declare(FastJets(fs, JetAlg::DURHAM, 0.7), "DurhamJets");
  const Thrust thrust(fs);
  declare(thrust, "Thrust");
  declare(Hemispheres(thrust), "Hemispheres");

  // Book histograms
  book(_h["thrust"], 1, 1, 1);
  book(_h["rho"], 2, 1, 1);
  book(_h["y23"], 3, 1, 1);

  _axes["thrust"] = YODA::Axis<double>(22, 0.8, 5.2);
  _axes["rho"] = YODA::Axis<double>(21, 1.0, 5.2);
  _axes["y23"] = YODA::Axis<double>(18, 1.2, 8.4);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  if (_edges.empty()) {
    for (const auto& item : _h) {
      _edges[item.first] = item.second->xEdges();
    }
  }
  // First, veto on leptonic events by requiring at least 4 charged FS particles
  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;
  }
  // thrust
  const Thrust& thrust = apply<Thrust>(event, "Thrust");
  fillhist("thrust", -log(1. - thrust.thrust()));
  // jet mass
  const Hemispheres& hemi = apply<Hemispheres>(event, "Hemispheres");
  fillhist("rho", -log(hemi.scaledM2high()));
  // Jets
  const FastJets& durjet = apply<FastJets>(event, "DurhamJets");
  if (numParticles >= 3) {
    if (durjet.clusterSeq()) fillhist("y23", -log(durjet.clusterSeq()->exclusive_ymerge_max(2)));
  }
}

void fillhist(const string& label, const double value) {
  string edge = "OTHER";
  const size_t idx = _axes[label].index(value);
  if (idx && idx <= _edges[label].size()) {
    edge = _edges[label][idx - 1];
  }
  _h[label]->fill(edge);
}


/// Normalise histograms etc., after the run
void finalize() {
  normalize(_h);
  for (auto& hist : _h) {
    for (auto& b : hist.second->bins()) {
      const size_t idx = b.index();
      b.scaleW(1. / _axes[hist.first].width(idx));
    }
  }
}

/// @}


/// @name Histograms
/// @{
map<string, BinnedHistoPtr<string>> _h;
map<string, YODA::Axis<double>> _axes;
map<string, vector<string>> _edges;
/// @}

};

RIVET_DECLARE_PLUGIN(TOPAZ_1993_I361661);

} ```