Rivet analyses

Measurement of R for energies between 9.41 and 10.63 GeV

Experiment: DESY147 (DORIS)

Inspire ID: 131524

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B78 (1978) 360-363, 1978

Beams: e- e+

Beam energies: (5.0, 5.0); (5.0, 5.0); (5.0, 5.0); (5.0, 5.0); (5.0, 5.0); (5.0, 5.0); (5.0, 5.0); (5.0, 5.0); (5.0, 5.0); (5.0, 5.0); (5.0, 5.0); (5.0, 5.0); (5.0, 5.0); (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); (4.8, 4.8); (4.8, 4.8); (5.0, 5.0)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 9.41 and 9.51, and 9.98 and 10.63 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:DESY147_1978_I131524.cc

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

namespace Rivet {


  /// @brief R measurement
  class DESY147_1978_I131524 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(DESY147_1978_I131524);


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

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

      // Book histograms
      for (size_t ix=0; ix<2; ++ix) {
        const auto& ref = refData<YODA::BinnedEstimate<string>>(1+ix,1,1);
        book(_c_hadrons[ix], "/TMP/sigma_hadrons_"+toString(ix+1), ref);
        book(_c_muons[ix],   "/TMP/sigma_muons_" +toString(ix+1),  ref);
        for (const string& en : _c_hadrons[ix].binning().edges<0>()) {
          double eval = stod(en);
          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;
      }
      // mu+mu- + photons
      if (nCount[-13]==1 and nCount[13]==1 && ntotal==2+nCount[22]) {
        for (size_t ix=0; ix<2; ++ix) _c_muons[ix]->fill(_sqs[ix]);
      }
      // everything else
      else {
        for (size_t ix=0;ix<2;++ix) _c_hadrons[ix]->fill(_sqs[ix]);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (size_t ix=-0; ix<2; ++ix) {
        BinnedEstimatePtr<string> mult;
        book(mult, 1+ix, 1, 1);
        divide(_c_hadrons[ix], _c_muons[ix], mult);
      }
    }

    /// @}


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


  };


  RIVET_DECLARE_PLUGIN(DESY147_1978_I131524);

}