Rivet analyses

ATLAS proton-lead centrality calibration analysis.

Experiment: ()

Status: UNVALIDATED

Authors: - Leif Lonnblad

References: - arXiv: 1508.00848

Beams: * *

Beam energies: ANY

Run details: - Any!

Calibration analysis for ATLAS pPb centrality. The centrality measure is ∑E⟂ in the lead direction. 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:ATLAS_CENT_PPB_CALIB.cc

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Analyses/AtlasCommon.hh"
#include "Rivet/Projections/ImpactParameterProjection.hh"

namespace Rivet {


  class ATLAS_CENT_PPB_CALIB : public Analysis {
  public:

    RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_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(ATLAS::SumET_PB_Centrality(), "Centrality");
      declare(ImpactParameterProjection(), "IMP");
      declare(ATLAS::MinBiasTrigger(), "Trigger");

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

      // 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) {

      // 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<ATLAS::MinBiasTrigger>(event, "Trigger")() ) vetoEvent;

      _calib->fill(apply<ATLAS::SumET_PB_Centrality>(event, "Centrality")());
    }


    /// Finalize
    void finalize() {
      if (_calib->integral())     _calib->normalize();
      if (_impcalib->integral())  _impcalib->normalize();
    }


  private:

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

  };


  RIVET_DECLARE_PLUGIN(ATLAS_CENT_PPB_CALIB);

}