Rivet analyses

title: PLUTO_1979_I142517

Measurement of $R$ between 22 and 31.6 GeV

Experiment: PLUTO (PETRA)

Inspire ID: 142517

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B86 (1979) 413-417, 1979

Beams: e- e+

Beam energies: (11.0, 11.0); (13.8, 13.8); (15.0, 15.0); (15.8, 15.8)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 22 and 31.6 GeV. The hadronic cross section is also measured in the $\Upsilon$ region, 9.3 to 9.48 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_I142517.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief Measurement of R class PLUTO_1979_I142517 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(PLUTO_1979_I142517);


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

/// Book histograms and initialise projections before the run
void init() {
  // Initialise and register projections
  declare(FinalState(), "FS");
  book(_c_hadrons, "sigma_hadrons", refData<YODA::BinnedEstimate<string>>(1, 1, 1));
  book(_c_muons, "sigma_muons", refData<YODA::BinnedEstimate<string>>(1, 1, 1));
  book(_mult, 1, 1, 1);
  for (const string& en : _c_hadrons.binning().edges<0>()) {
    const size_t idx = en.find("-");
    if (idx != string::npos) continue;
    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;
  }
  if (nCount[-13] == 1 && nCount[13] == 1 && ntotal == 2 + nCount[22]) {
    _c_muons->fill(_sqs); // mu+mu- + photons
    if (_sqs != "22.0"s) _c_muons->fill("-"s);
  }
  else {
    _c_hadrons->fill(_sqs); // everything else
    if (_sqs != "22.0"s) _c_hadrons->fill("-"s);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  scale({_c_hadrons, _c_muons}, crossSection() / sumOfWeights() / nanobarn);
  divide(_c_hadrons, _c_muons, _mult);
}

/// @}


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

};

RIVET_DECLARE_PLUGIN(PLUTO_1979_I142517); } ```