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TASSO_1979_I140303

Measurement of $R$ for energies between 13 and 17 GeV
Experiment: TASSO (PETRA)
Inspire ID: 140303
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett. B83 (1979) 261-266, 1979
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 for energies between 13 and 17 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: TASSO_1979_I140303.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 TASSO_1979_I140303 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(TASSO_1979_I140303);
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      // counters for R
24      book(_c_hadrons, "/TMP/sigma_hadrons");
25      book(_c_muons, "/TMP/sigma_muons");
26    }
27
28
29    /// Perform the per-event analysis
30    void analyze(const Event& event) {
31      const FinalState& fs = apply<FinalState>(event, "FS");
32
33      map<long,int> nCount;
34      int ntotal(0);
35      for (const Particle& p : fs.particles()) {
36        nCount[p.pid()] += 1;
37        ++ntotal;
38      }
39      if(nCount[-13]==1 and nCount[13]==1 && ntotal==2+nCount[22]) {
40        // mu+mu- + photons
41        _c_muons->fill();
42      }
43      else {
44        // everything else
45        _c_hadrons->fill();
46      }
47    }
48
49
50    /// Normalise histograms etc., after the run
51    void finalize() {
52      Estimate0D R = *_c_hadrons/ *_c_muons;
53      double fact = crossSection()/ sumOfWeights() /picobarn;
54      double sig_h = _c_hadrons->val()*fact;
55      double err_h = _c_hadrons->err()*fact;
56      double sig_m = _c_muons  ->val()*fact;
57      double err_m = _c_muons  ->err()*fact;
58      Estimate1DPtr hadrons;
59      book(hadrons, "sigma_hadrons");
60      Estimate1DPtr muons;
61      book(muons, "sigma_muons"  );
62      Estimate1DPtr mult;
63      book(mult, 1, 1, 1);
64      for (auto& b : mult->bins()) {
65        if (inRange(sqrtS()/GeV, b.xMin(), b.xMax())) {
66          b.set(R.val(), R.errPos());
67          hadrons->bin(b.index()).set(sig_h, err_h);
68          muons  ->bin(b.index()).set(sig_m, err_m);
69        }
70      }
71    }
72
73    /// @}
74
75
76    /// @name Histograms
77    /// @{
78    CounterPtr _c_hadrons, _c_muons;
79    /// @}
80
81
82  };
83
84
85  RIVET_DECLARE_PLUGIN(TASSO_1979_I140303);
86
87
88}