Rivet analyses

title: MARKJ_1980_I158857

Measurement of $R$ between 12 and 35.8 GeV

Experiment: MARKJ (PETRA)

Inspire ID: 158857

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rept. 63 (1980) 337-391, 1980

Beams: e- e+

Beam energies: (6.0, 6.0); (6.5, 6.5); (8.5, 8.5); (11.0, 11.0); (15.0, 15.0); (15.8, 15.8); (17.0, 17.0)GeV

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

Measurement of $R$ in $e^+e^-$ collisions by MARKJ between 12 and 35.8 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:MARKJ_1980_I158857.cc

```c++ // -- C++ --

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief R measurement class MARKJ_1980_I158857 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(MARKJ_1980_I158857);


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


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

/// @}


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

};

RIVET_DECLARE_PLUGIN(MARKJ_1980_I158857); } ```