1// -*- C++ -*-
 2#include "Rivet/Analyses/AtlasCommon.hh"
 3#include "Rivet/Projections/ImpactParameterProjection.hh"
 4#include "Rivet/Analysis.hh"
 5
 6namespace Rivet {
 7
 8
 9  class ATLAS_PBPB_CENTRALITY : public Analysis {
10
11  public:
12
13    RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_PBPB_CENTRALITY);
14
15    /// Book histograms and initialise projections before the run
16    void init() {
17
18      // One projection for the actual observable, and one for the
19      // generated impact parameter.
20      declare(ATLAS::SumET_PBPB_Centrality(), "Centrality");
21      declare(ImpactParameterProjection(), "IMP");
22      declare(ATLAS::MinBiasTrigger(), "Trigger");
23
24      // The calibration histogram:
25      book(_calib, "sumETFwd");
26
27      // The alternative histogram based on impact parameter. Note that
28      // it MUST be named the same as the histogram for the experimental
29      // observable with an added _IMP suffix for the Pecentile<>
30      // binning to work properly.
31      book(_impcalib, "sumETFwd_IMP", 400, 0.0, 20.0);
32
33    }
34
35    /// Perform the per-event analysis
36    void analyze(const Event& event) {
37
38      // The alternative centrality based on generated impact
39      // parameter, assumes that the generator does not describe the
40      // full final state, and should therefore be filled even if the
41      // event is not triggered.
42      _impcalib->fill(apply<SingleValueProjection>(event, "IMP")());
43
44      if ( !apply<ATLAS::MinBiasTrigger>(event, "Trigger")() ) vetoEvent;
45
46      _calib->fill(apply<ATLAS::SumET_PBPB_Centrality>(event, "Centrality")());
47
48    }
49
50    /// Finalize
51    void finalize() {
52
53      _calib->normalize();
54      _impcalib->normalize();
55
56    }
57
58  private:
59
60    /// The calibration histograms.
61    Histo1DPtr _calib;
62    Histo1DPtr _impcalib;
63
64  };
65
66
67  RIVET_DECLARE_PLUGIN(ATLAS_PBPB_CENTRALITY);
68
69}