1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief e+e- -> pi+pi-
 9  class KLOE_2009_I797438 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(KLOE_2009_I797438);
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(_npion, "TMP/pion", refData(1,1,1));
27
28    }
29
30
31    /// Perform the per-event analysis
32    void analyze(const Event& event) {
33      const FinalState& fs = apply<FinalState>(event, "FS");
34      if(fs.particles().size()!=2) vetoEvent;
35      for (const Particle& p : fs.particles()) {
36	if(abs(p.pid())!=PID::PIPLUS) vetoEvent;
37      }
38      _npion->fill(sqr(sqrtS()/GeV));
39    }
40
41
42    /// Normalise histograms etc., after the run
43    void finalize() {
44      scale(_npion, crossSection()/ sumOfWeights() /nanobarn);
45      Estimate1DPtr mult;
46      book(mult, 2, 1, 1);
47      barchart(_npion,mult);
48    }
49
50    /// @}
51
52
53    /// @name Histograms
54    /// @{
55    Histo1DPtr _npion;
56    /// @}
57
58
59  };
60
61
62  RIVET_DECLARE_PLUGIN(KLOE_2009_I797438);
63
64
65}