Rivet analyses

title: FENICE_1994_I377833

Cross section for $e^+e^-\to p\bar{p}$ between 1.9 and 2.44 GeV

Experiment: FENICE (ADONE)

Inspire ID: 377833

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B334 (1994) 431-434, 1994

Beams: e+ e-

Beam energies: (1.0, 1.0); (1.0, 1.0); (1.1, 1.1); (1.2, 1.2)GeV

Run details: - e+e- to hadrons

Measurement of the cross section for $e^+e^-\to p\bar{p}$ between 1.9 and 2.44 GeV.

Source code:FENICE_1994_I377833.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief e+e- -> p pbar class FENICE_1994_I377833 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(FENICE_1994_I377833);


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

/// Book histograms and initialise projections before the run
void init() {
  // Initialise and register projections
  declare(FinalState(), "FS");
  declare(UnstableParticles(), "UFS");
  book(_nProton, 1, 1, 1);
  for (const string& en : _nProton.binning().edges<0>()) {
    const double eval = sqrt(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");
  // total hadronic and muonic cross sections
  map<long, int> nCount;
  int ntotal(0);
  for (const Particle& p : fs.particles()) {
    ++nCount[p.pid()];
    ++ntotal;
  }
  if (ntotal == 2 && nCount[2212] == 1 && nCount[-2212] == 1) _nProton->fill(_sqs);
}


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

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _nProton;
string _sqs = "";
/// @}

};

RIVET_DECLARE_PLUGIN(FENICE_1994_I377833); } ```