Rivet analyses

Measurement of R between 30 and 31 GeV

Experiment: PLUTO (PETRA)

Inspire ID: 152291

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B91 (1980) 148-151, 1980

Beams: e- e+

Beam energies: ANY

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

Measurement of R in e+e− collisions by PLUTO for energies between 30 and 31 GeV. The individual hadronic and muonic cross sections are also outputted to the yoda file so that ratio R can be recalculated if runs are combined.

Source code:PLUTO_1980_I152291.cc

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

namespace Rivet {


  /// @brief R measurement
  class PLUTO_1980_I152291 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(PLUTO_1980_I152291);


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

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

      // Book histograms
      for (unsigned int ix = 0; ix < 2; ++ix) {
        book(_c_hadrons[ix], "/TMP/sigma_hadrons_" + toString(ix + 1), refData(1 + ix, 1, 1));
        book(_c_muons[ix], "/TMP/sigma_muons_" + toString(ix + 1), refData(1 + ix, 1, 1));
      }
    }


    /// 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]) {
        for (unsigned int ix = 0; ix < 2; ++ix) _c_muons[ix]->fill(sqrtS());
      }
      // everything else
      else {
        for (unsigned int ix = 0; ix < 2; ++ix) _c_hadrons[ix]->fill(sqrtS());
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 2; ++ix) {
        Estimate1DPtr mult;
        book(mult, ix + 1, 1, 1);
        divide(_c_hadrons[ix], _c_muons[ix], mult);
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _c_hadrons[2], _c_muons[2];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(PLUTO_1980_I152291);


}