Rivet analyses

Measurement of R between 3 and 17 GeV

Experiment: PLUTO (PETRA)

Inspire ID: 140294

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B81 (1979) 410-415, 1979

Beams: e- e+

Beam energies: (1.8, 1.8); (2.0, 2.0); (2.5, 2.5); (3.9, 3.9); (4.7, 4.7); (6.5, 6.5); (8.5, 8.5)GeV

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

Measurement of R in e+e− collisions by PLUTO for energies between 3 and 17 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_1979_I140294.cc

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

namespace Rivet {


  /// @brief R measurement
  class PLUTO_1979_I140294 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(PLUTO_1979_I140294);


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

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

      // Book histograms
      book(_c_hadrons1, "/TMP/sigma_hadrons1", refData<YODA::BinnedEstimate<string>>(1,1,1));
      book(_c_muons1,   "/TMP/sigma_muons1"  , refData<YODA::BinnedEstimate<string>>(1,1,1));
      book(_c_hadrons2, "/TMP/sigma_hadrons2", refData<YODA::BinnedEstimate<int>>(2,1,1));
      book(_c_muons2,   "/TMP/sigma_muons2"  , refData<YODA::BinnedEstimate<int>>(2,1,1));
      for (const string& en : _c_hadrons1.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;
      }
      if (nCount[-13]==1 && nCount[13]==1 && ntotal==2+nCount[22]) {
        // mu+mu- + photons
        _c_muons1->fill(_sqs);
        _c_muons2->fill(round(sqrtS()/GeV));
      }
      else {
        // everything else
        _c_hadrons1->fill(_sqs);
        _c_hadrons2->fill(round(sqrtS()/GeV));
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      BinnedEstimatePtr<string> mult1;
      book(mult1, 1, 1, 1);
      divide(_c_hadrons1, _c_muons1, mult1);
      BinnedEstimatePtr<int> mult2;
      book(mult2, 2, 1, 1);
      divide(_c_hadrons2, _c_muons2, mult2);
    }

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<string> _c_hadrons1, _c_muons1;
    BinnedHistoPtr<int>    _c_hadrons2, _c_muons2;
    string _sqs = "";
    /// @}


  };


  RIVET_DECLARE_PLUGIN(PLUTO_1979_I140294);
}