Rivet analyses

Measurement of the hadronic cross section near the NN̄ threshold

Experiment: FENICE (ADONE)

Inspire ID: 426675

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett.B 365 (1996) 427-430

Beams: e- e+

Beam energies: (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (1.0, 1.0); (1.0, 1.0); (1.1, 1.1); (1.2, 1.2)GeV

Run details: - e+ e- to hadrons

Measurement of hadronic cross section in e+e− collisions near the nucelon-antinucleon threshold by the FENICE experiment.

Source code:FENICE_1996_I426675.cc

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

namespace Rivet {


  /// @brief e+e- -> hadrons
  class FENICE_1996_I426675 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(FENICE_1996_I426675);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      declare(FinalState(), "FS");

      // Book histograms
      book(_c_hadrons, 1, 1, 1);
      for (const string& en : _c_hadrons.binning().edges<0>()) {
        const double eval = sqrt(stod(en));
        if (isCompatibleWithSqrtS(eval, 1e-3)) {
          _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()];
        ++ntotal;
      }
      // mu+mu- + photons
      if (nCount[-13]==1 and nCount[13]==1 && ntotal==2+nCount[22]) vetoEvent;
      _c_hadrons->fill(_sqs);
    }


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

    /// @}


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


  };


  RIVET_DECLARE_PLUGIN(FENICE_1996_I426675);
}