Rivet analyses

title: DM2_1983_I190558

Cross section for $e^+e^-\to p\bar{p}$ between 1.975 and 2.250 GeV

Experiment: DM2 (DCI)

Inspire ID: 190558

Status: VALIDATED

Authors: - Peter Richardson

References: - Nucl.Phys. B224 (1983) 379, 1983

Beams: e+ e-

Beam energies: ANY

Run details: - e+e- to hadrons

Source code:DM2_1983_I190558.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief e+ e- > p pbar class DM2_1983_I190558 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(DM2_1983_I190558);


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

/// Book histograms and initialise projections before the run
void init() {

  // Initialise and register projections
  declare(FinalState(), "FS");

  // Book histograms
  book(_nproton, "TMP/proton", refData(1, 1, 1));
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  const FinalState& fs = apply<FinalState>(event, "FS");
  if (fs.particles().size() != 2) vetoEvent;
  for (const Particle& p : fs.particles()) {
    if (abs(p.pid()) != PID::PROTON) vetoEvent;
  }
  _nproton->fill(sqrtS() / MeV);
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_nproton, crossSection() / sumOfWeights() / nanobarn);
  Estimate1DPtr mult;
  book(mult, 1, 1, 1);
  barchart(_nproton, mult);
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _nproton;
/// @}

};

RIVET_DECLARE_PLUGIN(DM2_1983_I190558);

} ```