Rivet analyses

Cross section for e+e− → π+π−, K+K− and pp̄ 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− → π+π−, K+K− and pp̄ at 3.671 GeV by CLEO-c.

Source code:CLEOC_2005_I693873.cc

// -*- 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);


}