Rivet analyses

Measurement of R between 3.6 and 30 GeV and hadronic cross section from 9.3 to 9.48 GeV

Experiment: PLUTO (PETRA)

Inspire ID: 166799

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rept. 83 (1982) 151-280, 1982

Beams: e- e+

Beam energies: (1.8, 1.8); (1.8, 1.8); (1.8, 1.8); (2.0, 2.0); (2.0, 2.0); (2.0, 2.0); (2.0, 2.0); (2.0, 2.0); (2.0, 2.0); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.3, 2.3); (2.3, 2.3); (2.3, 2.3); (2.3, 2.3); (2.4, 2.4); (2.5, 2.5); (3.9, 3.9); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (6.0, 6.0); (6.5, 6.5); (8.5, 8.5); (11.0, 11.0); (13.8, 13.8)GeV

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

Measurement of R in e+e− collisions for energies between 3.6 and 30 GeV. The hadronic cross section is also measured in the Υ region, 9.3 to 9.48 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:PLUTO_1982_I166799.cc

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

namespace Rivet {


  /// @brief R measurement
  class PLUTO_1982_I166799 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(PLUTO_1982_I166799);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      declare(FinalState(), "FS");
      // counters for R
      book(_c_hadrons[0], "/TMP/sigma_hadrons", refData<YODA::BinnedEstimate<string>>(1,1,1));
      book(_c_hadrons[1], 2,1,1);
      book(_c_muons, "/TMP/sigma_muons", refData<YODA::BinnedEstimate<string>>(1,1,1));
      for (size_t ix=0; ix<2; ++ix) {
        for (const string& en : _c_hadrons[ix].binning().edges<0>()) {
          const size_t idx = en.find("-");
          if (idx != string::npos) {
            const double emin = stod(en.substr(0,idx));
            const double emax = stod(en.substr(idx+1, string::npos));
            if (inRange(sqrtS()/GeV, emin, emax)) {
              _sqs[ix] = en; break;
            }
          }
          else {
            const double eval = stod(en)*GeV;
            if (isCompatibleWithSqrtS(eval)) {
              _sqs[ix] = en; break;
            }
          }
        }
      }
      raiseBeamErrorIf(_sqs[0].empty() && _sqs[1].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;
      }
      if (nCount[-13]==1 && nCount[13]==1 && ntotal==2+nCount[22]) {
        // mu+mu- + photons
        _c_muons->fill(_sqs[0]);
      }
      else {
        // everything else
        _c_hadrons[0]->fill(_sqs[0]);
        _c_hadrons[1]->fill(_sqs[1]);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_c_hadrons[1], crossSection()/sumOfWeights()/nanobarn);
      BinnedEstimatePtr<string> mult;
      book(mult, 1, 1, 1);
      divide(_c_hadrons[0], _c_muons, mult);
    }

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<string> _c_hadrons[2], _c_muons;
    string _sqs[2];
    /// @}


  };

  RIVET_DECLARE_PLUGIN(PLUTO_1982_I166799);
}