Rivet analyses

title: CLEOC_2005_I693873

Cross section for $e^+e^-\to \pi^+\pi^-$, $K^+K^-$ and $p\bar{p}$ at 3.671 GeV

Experiment: CLEOC (CESR)

Inspire ID: 693873

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 95 (2005) 261803

Beams: e- e+

Beam energies: (1.8, 1.8)GeV

Run details: - e+e- to hadrons

Measurement of the cross section for $e^+e^-\to \pi^+\pi^-$, $K^+K^-$ and $p\bar{p}$ at 3.671 GeV by CLEO-c.

Source code:CLEOC_2005_I693873.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief e+ e- > pi+pi-, K+K- and p pbar at 3.671 GeV class CLEOC_2005_I693873 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CLEOC_2005_I693873);


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

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

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

  // Book histograms
  book(_npipi, 1, 1, 1);
  book(_nKK, 1, 1, 2);
  book(_nppbar, 1, 1, 3);
}


/// 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) vetoEvent;

  if (nCount[211] == 1 && nCount[-211] == 1)
    _npipi->fill(ecms);
  else if (nCount[321] == 1 && nCount[-321] == 1)
    _nKK->fill(ecms);
  else if (nCount[2212] == 1 && nCount[-2212] == 1)
    _nppbar->fill(ecms);
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_npipi, crossSection() / sumOfWeights() / picobarn);
  scale(_nKK, crossSection() / sumOfWeights() / picobarn);
  scale(_nppbar, crossSection() / sumOfWeights() / picobarn);
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _npipi, _nKK, _nppbar;
string ecms = "3.671";
/// @}

};

RIVET_DECLARE_PLUGIN(CLEOC_2005_I693873);

} ```