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 e+ e- > pi+pi-
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", refData(1, 1, 1));
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(sqr(sqrtS()/GeV));
37    }
38
39    /// Normalise histograms etc., after the run
40    void finalize() {
41      scale( _npion, crossSection()/ sumOfWeights() /nanobarn);
42      Estimate1DPtr  mult;
43      book(mult, 1, 1, 1);
44      barchart(_npion,mult);
45    }
46
47    /// @}
48
49
50    /// @name Histograms
51    /// @{
52    Histo1DPtr _npion;
53    /// @}
54
55
56  };
57
58
59  RIVET_DECLARE_PLUGIN(KLOE2_2017_I1634981);
60
61
62}