Rivet analyses

title: PLUTO_1979_I140294

Measurement of $R$ between 3 and 17 GeV

Experiment: PLUTO (PETRA)

Inspire ID: 140294

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B81 (1979) 410-415, 1979

Beams: e- e+

Beam energies: (1.8, 1.8); (2.0, 2.0); (2.5, 2.5); (3.9, 3.9); (4.7, 4.7); (6.5, 6.5); (8.5, 8.5)GeV

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

Measurement of $R$ in $e^+e^-$ collisions by PLUTO for energies between 3 and 17 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_I140294.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief R measurement class PLUTO_1979_I140294 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(PLUTO_1979_I140294);


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

/// Book histograms and initialise projections before the run
void init() {
  // Initialise and register projections
  declare(FinalState(), "FS");

  // Book histograms
  book(_c_hadrons1, "/TMP/sigma_hadrons1", refData<YODA::BinnedEstimate<string>>(1, 1, 1));
  book(_c_muons1, "/TMP/sigma_muons1", refData<YODA::BinnedEstimate<string>>(1, 1, 1));
  book(_c_hadrons2, "/TMP/sigma_hadrons2", refData<YODA::BinnedEstimate<int>>(2, 1, 1));
  book(_c_muons2, "/TMP/sigma_muons2", refData<YODA::BinnedEstimate<int>>(2, 1, 1));
  for (const string& en : _c_hadrons1.binning().edges<0>()) {
    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]) {
    // mu+mu- + photons
    _c_muons1->fill(_sqs);
    _c_muons2->fill(round(sqrtS() / GeV));
  }
  else {
    // everything else
    _c_hadrons1->fill(_sqs);
    _c_hadrons2->fill(round(sqrtS() / GeV));
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  BinnedEstimatePtr<string> mult1;
  book(mult1, 1, 1, 1);
  divide(_c_hadrons1, _c_muons1, mult1);
  BinnedEstimatePtr<int> mult2;
  book(mult2, 2, 1, 1);
  divide(_c_hadrons2, _c_muons2, mult2);
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _c_hadrons1, _c_muons1;
BinnedHistoPtr<int> _c_hadrons2, _c_muons2;
string _sqs = "";
/// @}

};

RIVET_DECLARE_PLUGIN(PLUTO_1979_I140294); } ```