1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief Cross section for e+e- to proton and antiproton between 2 and 3.07 GeV
 9  class BESII_2005_I685906 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(BESII_2005_I685906);
14
15
16    /// @name Analysis methods
17    /// @{
18
19    /// Book histograms and initialise projections before the run
20    void init() {
21
22      // Initialise and register projections
23      declare(FinalState(), "FS");
24
25      // Book histograms
26      book(_nproton, 1, 1, 1);
27      for (const string& en : _nproton.binning().edges<0>()) {
28        const double end = std::stod(en)*GeV;
29        if (isCompatibleWithSqrtS(end)) {
30          _ecms = en;
31          break;
32        }
33      }
34      if (_ecms.empty())
35        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::PROTON) vetoEvent;
45      }
46      _nproton->fill(_ecms);
47    }
48
49
50    /// Normalise histograms etc., after the run
51    void finalize() {
52      scale(_nproton, crossSection()/ sumOfWeights() /picobarn);
53    }
54
55    /// @}
56
57
58    /// @name Histograms
59    /// @{
60    BinnedHistoPtr<string> _nproton;
61    string _ecms;
62    /// @}
63
64
65  };
66
67
68  RIVET_DECLARE_PLUGIN(BESII_2005_I685906);
69
70}