Rivet analyses

//-*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Analyses/AliceCommon.hh"
#include "Rivet/Projections/CentralityProjection.hh"

namespace Rivet {


  /// Pion, Kaon, and Proton Production in 0-5%
  ///  central Pb--Pb Collisions at 2.76 TeV
  class ALICE_2012_I1126966 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(ALICE_2012_I1126966);

    /// Book histograms and initialise projections before the run
    void init() {
      // Particles of interest.
      declare(ALICE::PrimaryParticles(Cuts::absrap < 0.5), "CFS");

      // The event trigger.
      declare(ALICE::V0AndTrigger(), "V0-AND");
      // The centrality projection.
      declareCentrality(ALICE::V0MMultiplicity(), "ALICE_2015_CENT_PBPB", "V0M", "V0M");

      // Invariant pT distributions.
      book(_histPtPi, "d01-x01-y01");        //pi+
      book(_histPtPibar, "d01-x01-y02");     // pi-
      book(_histPtKaon, "d02-x01-y01");      //K+
      book(_histPtKaonbar, "d02-x01-y02");   //K-
      book(_histPtProton, "d03-x01-y01");    //P+
      book(_histPtProtonbar, "d03-x01-y02"); //P-
      // Yield histograms.
      book(_histNpi, "d04-x01-y01");
      book(_histNpibar, "d04-x01-y02");
      book(_histNKaon, "d04-x01-y03");
      book(_histNKaonbar, "d04-x01-y04");
      book(_histNproton, "d04-x01-y05");
      book(_histNprotonbar, "d04-x01-y06");
      // Sum of weights of triggered events.
      book(sow, "sow");
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // Analysis only considers 0-5% central events
      if (apply<CentralityProjection>(event, "V0M")() > 5.0) vetoEvent;
      // Event trigger.
      if (!apply<ALICE::V0AndTrigger>(event, "V0-AND")()) vetoEvent;

      sow->fill();
      // ID particles counters for this event.
      int Npi = 0;
      int Npibar = 0;
      int NKaon = 0;
      int NKaonbar = 0;
      int Nproton = 0;
      int Nprotonbar = 0;

      for (const Particle& p : apply<ALICE::PrimaryParticles>(event, "CFS").particles()) {
        const double pWeight = 1.0 / p.pT() / 2. / M_PI;
        switch (p.pid()) {
          case 211: // pi+
            Npi++;
            _histPtPi->fill(p.pT() / GeV, pWeight);
            break;
          case -211: //pi-
            Npibar++;
            _histPtPibar->fill(p.pT() / GeV, pWeight);
            break;
          case 2212: // proton
            Nproton++;
            _histPtProton->fill(p.pT() / GeV, pWeight);
            break;
          case -2212: // p-bar
            Nprotonbar++;
            _histPtProtonbar->fill(p.pT() / GeV, pWeight);
            break;
          case 321: // K+
            NKaon++;
            _histPtKaon->fill(p.pT() / GeV, pWeight);
            break;
          case -321: // K-
            NKaonbar++;
            _histPtKaonbar->fill(p.pT() / GeV, pWeight);
            break;
        }
      } // Particle loop ends.

      // Fill yield histograms.
      _histNpi->fill(0.0, Npi);
      _histNpibar->fill(0.0, Npibar);
      _histNKaon->fill(0.0, NKaon);
      _histNKaonbar->fill(0.0, NKaonbar);
      _histNproton->fill(0.0, Nproton);
      _histNprotonbar->fill(0.0, Nprotonbar);
    }


    void finalize() {
      const double s = 1. / sow->sumW();
      _histPtPi->scaleW(s);
      _histPtPibar->scaleW(s);
      _histPtKaon->scaleW(s);
      _histPtKaonbar->scaleW(s);
      _histPtProton->scaleW(s);
      _histPtProtonbar->scaleW(s);
      _histNpi->scaleW(s);
      _histNpibar->scaleW(s);
      _histNKaon->scaleW(s);
      _histNKaonbar->scaleW(s);
      _histNproton->scaleW(s);
      _histNprotonbar->scaleW(s);
    }

  private:

    // pT histograms
    Histo1DPtr _histPtPi;
    Histo1DPtr _histPtKaon;
    Histo1DPtr _histPtProton;
    Histo1DPtr _histPtPibar;
    Histo1DPtr _histPtKaonbar;
    Histo1DPtr _histPtProtonbar;
    Histo1DPtr _histNpi;
    Histo1DPtr _histNpibar;
    Histo1DPtr _histNKaon;
    Histo1DPtr _histNKaonbar;
    Histo1DPtr _histNproton;
    Histo1DPtr _histNprotonbar;
    CounterPtr sow;
  };


  RIVET_DECLARE_PLUGIN(ALICE_2012_I1126966);


}