Rivet analyses

Measurement of R and the hadronic cross section for energies between 1.91 and 2.97 GeV

Experiment: GAMMAGAMMA (ADONE)

Inspire ID: 100016

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B58 (1975) 481-483, 1975

Beams: e- e+

Beam energies: ANY

Run details: - e+ e- to hadrons and e+ e- to mu+ mu- (for normalization)

Measurement of R and the hadronic cross section in e+e− collisions by the GAMMA-GAMMA group for energies between 1.91 and 2.97 GeV. The muonic cross section is also outputted to the yoda file so that ratio R can be recalcuated if runs are combined.

Source code:GAMMAGAMMA_1975_I100016.cc

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

namespace Rivet {


  /// @brief e+e- R
  class GAMMAGAMMA_1975_I100016 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(GAMMAGAMMA_1975_I100016);


    /// @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, "/TMP/sigma_hadrons", refData(1, 1, 2));
      book(_c_muons, "/TMP/sigma_muons", refData(1, 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]) _c_muons->fill(sqrtS() / GeV);
      // everything else
      else
        _c_hadrons->fill(sqrtS() / GeV);
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      Estimate1DPtr mult;
      book(mult, 1, 1, 2);
      divide(_c_hadrons, _c_muons, mult);
      double fact = crossSection() / sumOfWeights() / nanobarn;
      scale(_c_hadrons, fact);
      book(mult, 1, 1, 1);
      barchart(_c_hadrons, mult);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _c_hadrons, _c_muons;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(GAMMAGAMMA_1975_I100016);


}