Rivet analyses

Measurement of R for energies between 9.39 GeV

Experiment: CRYSTAL_BALL (DORIS)

Inspire ID: 261078

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B234 (1990) 525-533, 1990

Beams: e- e+

Beam energies: (4.7, 4.7)GeV

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

Measurement of R in e+e− collisions by the Crystal Ball experiment for 9.39 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:CRYSTAL_BALL_1988_I261078.cc

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

namespace Rivet {


  /// @brief R measurement
  class CRYSTAL_BALL_1988_I261078 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(CRYSTAL_BALL_1988_I261078);


    /// @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, "sigma_hadrons", refData<YODA::BinnedEstimate<string>>(1,1,1));
      book(_c_muons  , "sigma_muons"  , refData<YODA::BinnedEstimate<string>>(1,1,1));
    }


    /// 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 and nCount[13]==1 && ntotal==2+nCount[22]) {
        _c_muons->fill(Ecm); // mu+mu- + photons
      }
      else {
        _c_hadrons->fill(Ecm); // everything else
      }
    }


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


    /// @name Histograms
    /// @{
    BinnedHistoPtr<string> _c_hadrons, _c_muons;
    const string Ecm = "9.39";
    /// @}


  };


  RIVET_DECLARE_PLUGIN(CRYSTAL_BALL_1988_I261078);


}