Rivet analyses

Measurement of charged particle multiplicity vs thrust at ECMS = 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++ -*-
#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);


}