Rivet analyses

title: FENICE_1996_I426675

Measurement of the hadronic cross section near the $N\bar{N}$ threshold

Experiment: FENICE (ADONE)

Inspire ID: 426675

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett.B 365 (1996) 427-430

Beams: e- e+

Beam energies: (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (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 hadronic cross section in $e^+e^-$ collisions near the nucelon-antinucleon threshold by the FENICE experiment.

Source code:FENICE_1996_I426675.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief e+e- -> hadrons class FENICE_1996_I426675 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(FENICE_1996_I426675);


/// @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);
  for (const string& en : _c_hadrons.binning().edges<0>()) {
    const double eval = sqrt(stod(en));
    if (isCompatibleWithSqrtS(eval, 1e-3)) {
      _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;
  }
  // mu+mu- + photons
  if (nCount[-13] == 1 and nCount[13] == 1 && ntotal == 2 + nCount[22]) vetoEvent;
  _c_hadrons->fill(_sqs);
}


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

/// @}


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

};

RIVET_DECLARE_PLUGIN(FENICE_1996_I426675); } ```