Rivet analyses

title: SND_2006_I720035

Measurement of the cross section for $e^+e^-\to K_S^0K_L^0$ at energies between 1.04 and 1.38 GeV

Experiment: SND (VEPP-2M)

Inspire ID: 720035

Status: VALIDATED

Authors: - Peter Richardson

References: - J. Exp. Theor. Phys. 103, 720 (2006)

Beams: e+ e-

Beam energies: ANY

Run details: - e+e- to hadrons

Measurement of the cross section for $e^+e^-\to K_S^0K_L^0$ at energies between 1.04 and 1.38 GeV

Source code:SND_2006_I720035.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief e+e- > KS0 KL0 class SND_2006_I720035 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(SND_2006_I720035);


/// @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>()) {
    const size_t idx = en.find("-");
    if (idx != string::npos) {
      const double emin = stod(en.substr(0, idx));
      const double emax = stod(en.substr(idx + 1, string::npos));
      if (inRange(sqrtS() / GeV, emin, emax)) {
        _sqs = en;
        break;
      }
    }
    else {
      const 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(SND_2006_I720035); } ```