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Rivet analyses reference

CMD2_2002_I568807

Cross section for $e^+e^-\to \pi^+\pi^-$ at near the $\rho$ mass.
Experiment: CMD2 (VEPP-2M)
Inspire ID: 568807
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett. B527 (2002) 161-172, 2002
Beams: e+ e-
Beam energies: (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.3, 0.3); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.4, 0.4); (0.5, 0.5); (0.5, 0.5); (0.5, 0.5); (0.5, 0.5); (0.5, 0.5); (0.5, 0.5); (0.5, 0.5) GeV
Run details:
  • e+e- to hadrons

Measurement of the cross section for $e^+e^-\to \pi^+\pi^-$ at energies near the $\rho$ mass.

Source code: CMD2_2002_I568807.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4
 5
 6namespace Rivet {
 7
 8
 9  /// @brief Add a short analysis description here
10  class CMD2_2002_I568807 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(CMD2_2002_I568807);
15
16
17    /// @name Analysis methods
18    /// @{
19
20    /// Book histograms and initialise projections before the run
21    void init() {
22
23      // Initialise and register projections
24      declare(FinalState(), "FS");
25
26      // Book histograms
27      book(_npion, 1,1,2);
28      for (const string& en : _npion.binning().edges<0>()) {
29        double end = std::stod(en)*MeV;
30        if(isCompatibleWithSqrtS(end)) {
31          ecms = en;
32          break;
33        }
34      }
35      if(ecms.empty()) MSG_ERROR("Beam energy incompatible with analysis.");
36    }
37
38
39    /// Perform the per-event analysis
40    void analyze(const Event& event) {
41      const FinalState& fs = apply<FinalState>(event, "FS");
42      if(fs.particles().size()!=2) vetoEvent;
43      for (const Particle& p : fs.particles()) {
44	if(abs(p.pid())!=PID::PIPLUS) vetoEvent;
45      }
46      _npion->fill(ecms);
47    }
48
49
50    /// Normalise histograms etc., after the run
51    void finalize() {
52      scale(_npion,crossSection()/ sumOfWeights() /nanobarn);
53    }
54
55    /// @}
56
57
58    /// @name Histograms
59    /// @{
60    BinnedHistoPtr<string> _npion;
61    string ecms;
62    /// @}
63
64
65  };
66
67
68  RIVET_DECLARE_PLUGIN(CMD2_2002_I568807);
69
70
71}