1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/Beam.hh"
 4#include "Rivet/Projections/ChargedFinalState.hh"
 5
 6namespace Rivet {
 7
 8
 9  /// NA22 min bias multiplicity distributions.
10  class NA22_1986_I18431 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(NA22_1986_I18431);
15
16
17    /// @name Analysis methods
18    ///@{
19
20    /// Book histograms and initialise projections before the run
21    void init() {
22
23      declare(ChargedFinalState(), "CFS");
24
25      // Figure out beam type
26      const ParticlePair& beam = beams();
27      int btype = 0;
28      if (beam.first.pid() == PID::PIPLUS && beam.second.pid() == PID::PROTON)
29        btype = 1;
30      else if (beam.first.pid() == PID::KPLUS && beam.second.pid() == PID::PROTON)
31        btype = 2;
32      else if (beam.first.pid() == PID::PROTON && beam.second.pid() == PID::PROTON)
33        btype = 3;
34      else {
35        MSG_ERROR("Beam error: Not compatible!");
36        return;
37      }
38
39      // Book histo for appropriate beam type
40      book(_h_mult, btype, 1, 1);
41
42    }
43
44
45    /// Perform the per-event analysis
46    void analyze(const Event& event) {
47      size_t nfs = apply<ChargedFinalState>(event, "CFS").size();
48      if (nfs >= 30)  nfs = 30;
49      _h_mult->fill(nfs);
50    }
51
52
53    /// Normalise histograms etc., after the run
54    void finalize() {
55      normalize(_h_mult, 2.0); // normalize to 2 to account for bin width
56    }
57
58    ///@}
59
60
61    /// @name Histograms
62    //@{
63    Histo1DPtr _h_mult;
64    //@}
65
66
67  };
68
69
70  // The hook for the plugin system
71  RIVET_DECLARE_PLUGIN(NA22_1986_I18431);
72
73
74}