Rivet analyses

Measurement of R between 12 and 42.63 GeV

Experiment: MARKJ (PETRA)

Inspire ID: 196567

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rept. 109 (1984) 131, 1984

Beams: e- e+

Beam energies: (6.0, 6.0); (7.0, 7.0); (11.0, 11.0); (12.5, 12.5); (15.3, 15.3); (16.5, 16.5); (16.9, 16.9); (17.3, 17.3); (17.5, 17.5); (18.2, 18.2); (19.1, 19.1); (20.2, 20.2); (20.8, 20.8); (21.3, 21.3)GeV

Run details: - e+ e- to hadrons and e+ e- to mu+ mu- (for normalization)

Measurement of R in e+e− collisions by MARKJ between 42.63 GeV. The individual hadronic and muonic cross sections are also outputted to the yoda file so that ratio R can be recalculated if runs are combined.

Source code:MARKJ_1984_I196567.cc

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"

namespace Rivet {


  /// @brief R measurement
  class MARKJ_1984_I196567 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(MARKJ_1984_I196567);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      declare(FinalState(), "FS");

      // Book histograms
      book(_c_hadrons, "/TMP/sigma_hadron", refData<YODA::BinnedEstimate<string>>(1,1,1));
      book(_c_muons,   "/TMP/sigma_muons" , refData<YODA::BinnedEstimate<string>>(1,1,1));
      for (const string& en : _c_hadrons.binning().edges<0>()) {
        double eval = stod(en)*GeV;
        if (isCompatibleWithSqrtS(eval)) {
          _sqs = en; break;
        }
      }
      raiseBeamErrorIf(_sqs.empty());
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const FinalState& fs = apply<FinalState>(event, "FS");

      map<long,int> nCount;
      int ntotal(0);
      for (const Particle& p : fs.particles()) {
        nCount[p.pid()] += 1;
        ++ntotal;
      }
      // mu+mu- + photons
      if (nCount[-13]==1 && nCount[13]==1 && ntotal==2+nCount[22]) {
        _c_muons->fill(_sqs);
      }
      else _c_hadrons->fill(_sqs); // everything else
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      BinnedEstimatePtr<string> mult;
      book(mult, 1, 1, 1);
      divide(_c_hadrons, _c_muons, mult);
      scale(_c_hadrons, crossSection()/sumOfWeights()/nanobarn);
    }

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<string> _c_hadrons, _c_muons;
    string _sqs = "";
    /// @}


  };


  RIVET_DECLARE_PLUGIN(MARKJ_1984_I196567);
}