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 BESIII_2021_I1847766 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2021_I1847766);
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, "TMP/proton", 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      if(fs.particles().size()!=2) vetoEvent;
34      for (const Particle& p : fs.particles()) {
35	if(abs(p.pid())!=PID::PROTON) vetoEvent;
36      }
37      _nproton->fill(sqrtS()/GeV);
38    }
39
40
41    /// Normalise histograms etc., after the run
42    void finalize() {
43      scale(_nproton, crossSection()/ sumOfWeights() /picobarn);
44      Estimate1DPtr  mult;
45      book(mult, 1, 1, 1);
46      barchart(_nproton,mult);
47    }
48
49    ///@}
50
51
52    /// @name Histograms
53    ///@{
54    Histo1DPtr _nproton;
55    ///@}
56
57
58  };
59
60
61  RIVET_DECLARE_PLUGIN(BESIII_2021_I1847766);
62
63}