1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4#include "Rivet/Projections/FastJets.hh"
 5
 6namespace Rivet {
 7
 8
 9  /// @brief Add a short analysis description here
10  class KLOE2_2017_I1634981 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(KLOE2_2017_I1634981);
15
16
17    /// @name Analysis methods
18    /// @{
19
20    /// Book histograms and initialise projections before the run
21    void init() {
22      // Initialise and register projections
23      declare(FinalState(), "FS");
24
25      // Book histograms
26      book(_npion, "TMP/pion");
27    }
28
29    /// Perform the per-event analysis
30    void analyze(const Event& event) {
31      const FinalState& fs = apply<FinalState>(event, "FS");
32      if(fs.particles().size()!=2) vetoEvent;
33      for (const Particle& p : fs.particles()) {
34	if(abs(p.pid())!=PID::PIPLUS) vetoEvent;
35      }
36      _npion->fill();
37    }
38
39    /// Normalise histograms etc., after the run
40    void finalize() {
41      double sigma = _npion->val();
42      double error = _npion->err();
43      sigma *= crossSection()/ sumOfWeights() /nanobarn;
44      error *= crossSection()/ sumOfWeights() /nanobarn;
45      Estimate1DPtr  mult;
46      book(mult, 1, 1, 1);
47      for (auto& b : mult->bins()) {
48        if (inRange(sqr(sqrtS()/GeV), b.xMin(), b.xMax())) {
49          b.set(sigma, error);
50        }
51      }
52    }
53
54    /// @}
55
56
57    /// @name Histograms
58    /// @{
59    CounterPtr _npion;
60    /// @}
61
62
63  };
64
65
66  RIVET_DECLARE_PLUGIN(KLOE2_2017_I1634981);
67
68
69}