rivet is hosted by Hepforge, IPPP Durham

Rivet analyses reference

GAMMAGAMMA_1975_I100016

Measurement of $R$ and the hadronic cross section for energies between 1.91 and 2.97 GeV
Experiment: GAMMAGAMMA (ADONE)
Inspire ID: 100016
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett. B58 (1975) 481-483, 1975
Beams: e- e+
Beam energies: ANY
Run details:
  • e+ e- to hadrons and e+ e- to mu+ mu- (for normalization)

Measurement of $R$ and the hadronic cross section in $e^+e^-$ collisions by the GAMMA-GAMMA group for energies between 1.91 and 2.97 GeV. The muonic cross section is also outputted to the yoda file so that ratio $R$ can be recalcuated if runs are combined.

Source code: GAMMAGAMMA_1975_I100016.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief e+e- R
 9  class GAMMAGAMMA_1975_I100016 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(GAMMAGAMMA_1975_I100016);
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(1,1,2));
26      book(_c_muons, "/TMP/sigma_muons", refData(1,1,2));
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, 2);
54      divide(_c_hadrons, _c_muons, mult);
55      double fact = crossSection()/ sumOfWeights() /nanobarn;
56      scale(_c_hadrons,fact);
57      book(mult, 1, 1, 1);
58      barchart(_c_hadrons,mult);
59    }
60
61    /// @}
62
63
64    /// @name Histograms
65    /// @{
66    Histo1DPtr _c_hadrons, _c_muons;
67    /// @}
68
69
70  };
71
72
73  RIVET_DECLARE_PLUGIN(GAMMAGAMMA_1975_I100016);
74
75
76}