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MARKII_1991_I295286

Measurement of $R$ at 29 GeV
Experiment: MARKII (PEP)
Inspire ID: 295286
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Rev. D43 (1991) 34-45, 1991
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 MARKII at 29 GeV. The individual hadronic and muonic cross sections are also outputted to the yoda file so that ratio $R$ can be recalcuated if runs are combined.

Source code: MARKII_1991_I295286.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief Add a short analysis description here
 9  class MARKII_1991_I295286 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(MARKII_1991_I295286);
14
15
16    /// @name Analysis methods
17    /// @{
18
19    /// Book histograms and initialise projections before the run
20    void init() {
21      // Initialise and register projections
22      declare(FinalState(), "FS");
23
24      // Book histograms
25      book(_c_hadrons, "sigma_hadrons", refData<YODA::BinnedEstimate<int>>(1,1,1));
26      book(_c_muons, "sigma_muons", refData<YODA::BinnedEstimate<int>>(1,1,1));
27    }
28
29
30    /// Perform the per-event analysis
31    void analyze(const Event& event) {
32      const FinalState& fs = apply<FinalState>(event, "FS");
33
34      map<long,int> nCount;
35      int ntotal(0);
36      for (const Particle& p : fs.particles()) {
37        nCount[p.pid()] += 1;
38        ++ntotal;
39      }
40      if (nCount[-13]==1 and nCount[13]==1 && ntotal==2+nCount[22]) {
41        _c_muons->fill(29); // mu+mu- + photons
42      }
43      else {
44        _c_hadrons->fill(29); // everything else
45      }
46    }
47
48
49    /// Normalise histograms etc., after the run
50    void finalize() {
51      const double fact = crossSection()/sumOfWeights()/picobarn;
52      scale({_c_hadrons, _c_muons}, fact);
53      BinnedEstimatePtr<int> mult;
54      book(mult, 1, 1, 1);
55      divide(_c_hadrons, _c_muons, mult);
56    }
57
58    /// @}
59
60
61    /// @name Histograms
62    /// @{
63    BinnedHistoPtr<int> _c_hadrons, _c_muons;
64    /// @}
65
66
67  };
68
69
70  RIVET_DECLARE_PLUGIN(MARKII_1991_I295286);
71
72
73}