Rivet analyses

Measurement of the cc̄ cross section at 10.5 GeV

Experiment: CLEO (CESR)

Inspire ID: 23509

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.D 38 (1988) 2679

Beams: e+ e-

Beam energies: (5.2, 5.2)GeV

Run details: - e+ e- > hadrons

Measurement of cc̄ cross section at 10.5 GeV, the ratio to the μ+μ− cross section is also measured.

Source code:CLEO_1988_I23509.cc

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief e+ e- > c cbar at 10.52 GeV
  class CLEO_1988_I23509 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(CLEO_1988_I23509);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projections
      declare(FinalState(), "FS");
      declare(UnstableParticles(Cuts::abspid == 411 || Cuts::abspid == 421 || Cuts::abspid == 431
                                || Cuts::abspid == 4122 || Cuts::abspid == 4232 || Cuts::abspid == 4132
                                || Cuts::abspid == 4332),
              "UFS");
      // histos
      for (unsigned int ix = 0; ix < 2; ++ix) {
        book(_h[ix], 2 + ix, 1, 1);
      }
      book(_h[2], "TMP/h_mu", refData<YODA::BinnedEstimate<string>>(2, 1, 2));
    }


    /// 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;
      }
      // mu+mu- + photons
      if (nCount[-13] == 1 and nCount[13] == 1 && ntotal == 2 + nCount[22]) {
        _h[2]->fill("10.5"s);
      }
      else { // everything else
        const FinalState& ufs = apply<FinalState>(event, "UFS");
        if (!ufs.particles().empty()) {
          _h[0]->fill("10.5"s);
          _h[1]->fill("10.5"s);
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h, crossSection() / sumOfWeights() / nanobarn);
      BinnedEstimatePtr<string> tmp;
      book(tmp, 2, 1, 2);
      divide(_h[0], _h[2], tmp);
      book(tmp, 3, 1, 2);
      divide(_h[1], _h[2], tmp);
    }

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<string> _h[3];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(CLEO_1988_I23509);

}