rivet is hosted by Hepforge, IPPP Durham

Rivet analyses reference

MC_Cent_pPb_Calib

Template analysis for generating calibration histograms for centrality
Experiment: ()
Status: UNVALIDATED
Authors:
  • Leif Lönnblad
References:
  • arXiv: 1508.00848
  • Eur.Phys.J. C76 (2016) no.4, 199
Beams: * *
Beam energies: ANY
Run details:
  • Any!

Template analysis for generating calibration histograms to be used together with the CentralityProjection and Percentile<> classes. The example is pPb collisions at 5 TeV and is based on the ATLAS analysis arXiv:1508.00848 [hep-ex]. The reference YODA file contains the experimental centrality calibration, but extracted from the plot in the paper. Note that this has not been unfolded for detector effects.

Source code: MC_Cent_pPb_Calib.cc
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Analyses/MC_Cent_pPb.hh"
#include "Rivet/Projections/ImpactParameterProjection.hh"

namespace Rivet {


/// Generic analysis looking at various distributions of final state particles
class MC_Cent_pPb_Calib : public Analysis {

public:

  DEFAULT_RIVET_ANALYSIS_CTOR(MC_Cent_pPb_Calib);

  /// Book histograms and initialise projections before the run
  void init() {

    // One projection for the actual observable, and one for the
    // generated impact parameter.
    declare(MC_SumETFwdPbCentrality(), "Centrality");
    declare(ImpactParameterProjection(), "IMP");
    declare(MC_pPbMinBiasTrigger(), "Trigger");

    // The calibrationhistogram:
    book(_calib, "SumETPb", 100, 0.0, 200.0);

    // If histogram was pre-loaded, the calibration is done.
    _done = ( _calib->numEntries() > 0 );

    // The alternative histogram based on impact parameter. Note that
    // it MUST be named the same as the histogram for the experimental
    // observable with an added _IMP suffix for the Pecentile<>
    // binning to work properly.
    book(_impcalib, "SumETPb_IMP", 400, 0.0, 20.0);


  }
  
  /// Perform the per-event analysis
  void analyze(const Event& event) {

    if ( _done ) return;
    
    // The alternative centrality based on generated impact
    // parameter, assumes that the generator does not describe the
    // full final state, and should therefore be filled even if the
    // event is not triggered.
    _impcalib->fill(apply<SingleValueProjection>(event, "IMP")());

    if ( !apply<TriggerProjection>(event, "Trigger")() ) vetoEvent;

    _calib->fill(apply<SingleValueProjection>(event, "Centrality")());

  }
  
  /// Finalize
  void finalize() {

    _calib->normalize();
    _impcalib->normalize();

  }

private:

  /// The calibration histograms.
  Histo1DPtr _calib;
  Histo1DPtr _impcalib;

  /// Safeguard from adding to a pre-loaded histogram.
  bool _done;

};


// The hook for the plugin system
DECLARE_RIVET_PLUGIN(MC_Cent_pPb_Calib);

}