Rivet analyses

title: MARKII_1991_I295286

Measurement of $R$ at 29 GeV

Experiment: MARKII (PEP)

Inspire ID: 295286

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev. D43 (1991) 34-45, 1991

Beams: e- e+

Beam energies: ANY

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

Measurement of $R$ in $e^+e^-$ collisions by MARKII at 29 GeV. 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:MARKII_1991_I295286.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief Add a short analysis description here class MARKII_1991_I295286 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(MARKII_1991_I295286);


/// @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<int>>(1, 1, 1));
  book(_c_muons, "sigma_muons", refData<YODA::BinnedEstimate<int>>(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(29); // mu+mu- + photons
  }
  else {
    _c_hadrons->fill(29); // everything else
  }
}


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

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<int> _c_hadrons, _c_muons;
/// @}

};

RIVET_DECLARE_PLUGIN(MARKII_1991_I295286);

} ```