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TOPAZ_1993_I353845

Cross section in $e^+e^-\to$hadrons for energies between 57.37 and 59.84 GeV
Experiment: TOPAZ (Tristan)
Inspire ID: 353845
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett. B304 (1993) 373-380, 1993
Beams: e- e+
Beam energies: (28.7, 28.7); (28.9, 28.9); (29.0, 29.0); (29.1, 29.1); (29.2, 29.2); (29.4, 29.4); (29.5, 29.5); (29.6, 29.6); (29.7, 29.7); (29.9, 29.9) GeV
Run details:
  • e+ e- to hadrons and e+ e- to mu+ mu-

Measurement of the hadronic cross section in $e^+e^-$ collisions by TOPAZ for energies between 57.37 and 59.84 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: TOPAZ_1993_I353845.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief R measurement
 9  class TOPAZ_1993_I353845 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(TOPAZ_1993_I353845);
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, 2, 1, 1);
26      book(_c_muons,   4, 1, 1);
27      for (const string& en : _c_hadrons.binning().edges<0>()) {
28        double end = std::stod(en)*GeV;
29        if(isCompatibleWithSqrtS(end)) {
30          _ecms = en;
31          break;
32        }
33      }
34      if(_ecms.empty()) MSG_ERROR("Beam energy incompatible with analysis.");
35    }
36
37
38    /// Perform the per-event analysis
39    void analyze(const Event& event) {
40      const FinalState& fs = apply<FinalState>(event, "FS");
41
42      map<long,int> nCount;
43      int ntotal(0);
44      for (const Particle& p : fs.particles()) {
45	nCount[p.pid()] += 1;
46	++ntotal;
47      }
48      // mu+mu- + photons
49      if(nCount[-13]==1 and nCount[13]==1 &&
50	 ntotal==2+nCount[22])
51	_c_muons->fill(_ecms);
52      // everything else
53      else
54	_c_hadrons->fill(_ecms);
55    }
56
57
58    /// Normalise histograms etc., after the run
59    void finalize() {
60      double fact = crossSection()/ sumOfWeights() /picobarn;
61      scale(_c_hadrons, fact);
62      scale(_c_muons,   fact);
63    }
64
65    /// @}
66
67
68    /// @name Histograms
69    /// @{
70    BinnedHistoPtr<string> _c_hadrons, _c_muons;
71    string _ecms;
72    /// @}
73
74
75  };
76
77
78  RIVET_DECLARE_PLUGIN(TOPAZ_1993_I353845);
79
80
81}