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MD1_1986_I364141

Measurement of $R$ for energies between 7.2 and 10.34 GeV
Experiment: MD1 (VEPP-4)
Inspire ID: 364141
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Z.Phys. C70 (1996) 31-38, 1996
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 MD1 for energies between 7.2 and 10.34 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: MD1_1986_I364141.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 MD1_1986_I364141 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(MD1_1986_I364141);
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, "/TMP/sigma_hadrons",refData(1,1,1));
26      book(_c_muons, "/TMP/sigma_muons"    ,refData(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      // mu+mu- + photons
41      if(nCount[-13]==1 and nCount[13]==1 &&
42	 ntotal==2+nCount[22])
43	_c_muons->fill(sqrtS()/GeV);
44      // everything else
45      else
46	_c_hadrons->fill(sqrtS()/GeV);
47    }
48
49
50    /// Normalise histograms etc., after the run
51    void finalize() {
52      Estimate1DPtr mult;
53      book(mult, 1, 1, 1);
54      divide(_c_hadrons,_c_muons,mult);
55    }
56
57    /// @}
58
59
60    /// @name Histograms
61    /// @{
62    Histo1DPtr _c_hadrons, _c_muons;
63    /// @}
64
65
66  };
67
68
69  RIVET_DECLARE_PLUGIN(MD1_1986_I364141);
70
71
72}