Rivet analyses

title: SND_2005_I686349

Cross section for $e^+e^-\to \pi^+\pi^-$ at energies between 0.4 and 1 GeV

Experiment: SND (VEPP-2M)

Inspire ID: 686349

Status: VALIDATED

Authors: - Peter Richardson

References: - J. Exp. Theor. Phys. 101, 1053 (2005)

Beams: e+ e-

Beam energies: (0.2, 0.2); (0.2, 0.2); (0.2, 0.2); (0.2, 0.2); (0.2, 0.2); (0.2, 0.2); (0.2, 0.2); (0.2, 0.2); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.5, 0.5); (0.5, 0.5); (0.5, 0.5); (0.5, 0.5); (0.5, 0.5)GeV

Run details: - e+e- to hadrons

Source code:SND_2005_I686349.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief e+e- -> pi+pi- class SND_2005_I686349 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(SND_2005_I686349);


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

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

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

  // Book histograms
  book(_npion, 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::PIPLUS) vetoEvent;
  }
  _npion->fill(round(sqrtS() / MeV));
}


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

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<int> _npion;
/// @}

};

RIVET_DECLARE_PLUGIN(SND_2005_I686349);

} ```