Rivet analyses

title: MUPI_1972_I84978

Measurement of $R$ and the hadronic cross section for energies between 1.2 and 2.1 GeV

Experiment: MUPI (ADONE)

Inspire ID: 84978

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B218 (1989) 499-507, 1989

Beams: e- e+

Beam energies: (0.6, 0.6); (0.8, 0.8); (0.9, 0.9); (1.1, 1.1)GeV

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

Measurement of $R$ and the hadronic cross seection in $e^+e^-$ collisions by the Mu-Pi group for energies between 1.2 and 2.1 GeV.

Source code:MUPI_1972_I84978.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief e+e- R measurement class MUPI_1972_I84978 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(MUPI_1972_I84978);


/// @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, 1, 1, 1);
  book(_c_muons, "/TMP/sigma_muons", refData<YODA::BinnedEstimate<string>>(2, 1, 1));
  for (const string& en : _c_hadrons.binning().edges<0>()) {
    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);
  for (const Particle& p : fs.particles()) {
    ++nCount[p.pid()];
    ++ntotal;
  }
  if (nCount[-13] == 1 && nCount[13] == 1 && ntotal == 2 + nCount[22]) { // mu+mu- + photons
    _c_muons->fill(_sqs);
  }
  else { // everything else
    _c_hadrons->fill(_sqs);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  BinnedEstimatePtr<string> mult;
  book(mult, 2, 1, 1);
  divide(_c_hadrons, _c_muons, mult);
  scale(_c_hadrons, crossSection() / sumOfWeights() / nanobarn);
}

/// @}


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

};

RIVET_DECLARE_PLUGIN(MUPI_1972_I84978);

} ```