Rivet analyses

title: CMD2_2003_I601222

Cross section for $e^+e^-\to K^0_SK^0_L$ at energies between 1.05 and 1.38 GeV

Experiment: CMD2 (VEPP-2M)

Inspire ID: 601222

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B551 (2003) 27-34, 2003

Beams: e+ e-

Beam energies: (0.5, 0.5); (0.5, 0.5); (0.5, 0.5); (0.5, 0.5); (0.5, 0.5); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.7, 0.7); (0.7, 0.7)GeV

Run details: - e+e- to hadrons

Measurement of the cross section for $e^+e^-\to K^0_SK^0_L$ at energies between 1.05 and 1.38 GeV.

Source code:CMD2_2003_I601222.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief e+e- > KS0 KL0 class CMD2_2003_I601222 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CMD2_2003_I601222);


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

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

  declare(FinalState(), "FS");
  book(_nK0K0, 1, 1, 1);

  for (const string& en : _nK0K0.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 (ntotal == 2 && nCount[130] == 1 && nCount[310] == 1) _nK0K0->fill(_sqs);
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_nK0K0, crossSection() / sumOfWeights() / nanobarn);
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _nK0K0;
string _sqs = "";
/// @}

};

RIVET_DECLARE_PLUGIN(CMD2_2003_I601222); } ```