Rivet analyses

Measurement of R and the hadron multiplicity between 1.42 and 3.09 GeV

Experiment: GAMMAGAMMA (ADONE)

Inspire ID: 141722

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B86 (1979) 234-238, 1979

Beams: e- e+

Beam energies: (0.7, 0.7); (0.7, 0.7); (0.7, 0.7); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (1.0, 1.0); (1.0, 1.0); (1.1, 1.1); (1.1, 1.1); (1.3, 1.3); (1.3, 1.3); (1.4, 1.4); (1.5, 1.5)GeV

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

Measurement of R in e+e− collisions by Gamma-Gamma-2 for energies between 1.42 and 3.09 GeV. The average charged and neutral particle multiplicity is also measured. The individual hadronic and muonic cross sections are also outputted to the yoda file so that ratio R can be recalcuated if runs are combined.

Source code:GAMMAGAMMA_1979_I141722.cc

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

namespace Rivet {


  /// @brief R and hadron mult in e+e-
  class GAMMAGAMMA_1979_I141722 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(GAMMAGAMMA_1979_I141722);


    /// @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_hadrons", refData<YODA::BinnedEstimate<string>>(1,1,1));
      book(_c_muons  , "/TMP/sigma_muons"  , refData<YODA::BinnedEstimate<string>>(1,1,1));
      book(_c_charged, 2, 1, 1);
      book(_c_neutral, 2, 1, 2);
      for (const string& en : _c_hadrons.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 = en; break;
          }
        }
        else {
          const double eval= stod(en);
          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), ncharged(0), nneutral(0);
      for (const Particle& p : fs.particles()) {
        ++nCount[p.pid()];
        ++ntotal;
        if (PID::isCharged(p.pid())) ++ncharged;
        else                         ++nneutral;
      }
      // mu+mu- + photons
      if (nCount[-13]==1 and nCount[13]==1 && ntotal==2+nCount[22]) _c_muons->fill(_sqs);
      // everything else
      else {
        if (ntotal==2) vetoEvent;
        _c_hadrons->fill(_sqs);
        _c_charged->fill(sqrtS()/GeV,ncharged);
        _c_neutral->fill(sqrtS()/GeV,nneutral);
      }
    }


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

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<string> _c_hadrons, _c_muons;
    Profile1DPtr _c_neutral,_c_charged;
    string _sqs = "";
    /// @}


  };


  RIVET_DECLARE_PLUGIN(GAMMAGAMMA_1979_I141722);
}