Rivet analyses

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
#include "Rivet/Projections/SmearedParticles.hh"

namespace Rivet {


  /// Multiplicities and pT spectra from STAR for pp at 200 GeV
  class STAR_2008_I793126 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(STAR_2008_I793126);


    /// @name Analysis methods
    /// @{

    /// Book histograms and initialise projections before the run
    void init() {
      const ChargedFinalState cfs(Cuts::abseta < 0.5 && Cuts::pT > 0.2 * GeV);
      const SmearedParticles lfs(cfs, [](const Particle& p) {
        // Track reconstruction efficiencies for tracks with pT from 0 to 600 MeV
        // in steps of 50 MeV. The efficiency is assumed to be 0.88 for pT >= 600 MeV
        const static vector<double> TRKEFF = {0,    0,    0.38, 0.72, 0.78, 0.81,
                                              0.82, 0.84, 0.85, 0.86, 0.87, 0.88};
        const size_t idx = size_t(min(floor(p.pT() / MeV / 50), 11.));
        return TRKEFF[idx];
      });
      declare(lfs, "FS");

      book(_h_dNch, 1, 1, 1);
      book(_h_dpT_Pi, 2, 1, 1);
      book(_h_dpT_Piplus, 2, 1, 2);
      book(_h_dpT_Kaon, 2, 1, 3);
      book(_h_dpT_Kaonplus, 2, 1, 4);
      book(_h_dpT_AntiProton, 2, 1, 5);
      book(_h_dpT_Proton, 2, 1, 6);
      // book(nCutsPassed, "nCutsPassed");
      // book(nPi, "nPi");
      // book(nPiPlus, "nPiPlus");
      // book(nKaon, "nKaon");
      // book(nKaonPlus, "nKaonPlus");
      // book(nProton, "nProton");
      // book(nAntiProton, "nAntiProton");
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const ParticleFinder& charged = apply<ParticleFinder>(event, "FS");

      // Vertex reconstruction efficiencies as a function of charged multiplicity.
      // For events with more than 23 reconstructed tracks the efficiency is 100%.
      double vtxeffs[24] = {0.000000, 0.512667, 0.739365, 0.847131, 0.906946, 0.940922, 0.959328, 0.96997,
                            0.975838, 0.984432, 0.988311, 0.990327, 0.990758, 0.995767, 0.99412,  0.992271,
                            0.996631, 0.994802, 0.99635,  0.997384, 0.998986, 0.996441, 0.994513, 1.000000};

      double vtxeff = 1.0;
      if (charged.particles().size() < 24) {
        vtxeff = vtxeffs[charged.particles().size()];
      }

      const double weight = vtxeff;

      for (const Particle& p : charged.particles()) {
        double pT = p.pT() / GeV;
        double y = p.rapidity();
        if (fabs(y) < 0.1) {
          // nCutsPassed->fill(weight);
          const PdgId id = p.pid();
          switch (id) {
            case -211:
              _h_dpT_Pi->fill(pT, weight / (TWOPI * pT * 0.2));
              // nPi->fill(weight);
              break;
            case 211:
              _h_dpT_Piplus->fill(pT, weight / (TWOPI * pT * 0.2));
              // nPiPlus->fill(weight);
              break;
            case -321:
              _h_dpT_Kaon->fill(pT, weight / (TWOPI * pT * 0.2));
              // nKaon->fill(weight);
              break;
            case 321:
              _h_dpT_Kaonplus->fill(pT, weight / (TWOPI * pT * 0.2));
              // nKaonPlus->fill(weight);
              break;
            case -2212:
              _h_dpT_AntiProton->fill(pT, weight / (TWOPI * pT * 0.2));
              // nAntiProton->fill(weight);
              break;
            case 2212:
              _h_dpT_Proton->fill(pT, weight / (TWOPI * pT * 0.2));
              // nProton->fill(weight);
              break;
          }
        }
        else {
          continue;
        }
      }
      _h_dNch->fill(charged.particles().size(), weight);
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      //double nTot = nPi + nPiPlus + nKaon + nKaonPlus + nProton + nAntiProton;
      normalize(_h_dNch);

      /// @todo Norm to data!
      normalize(_h_dpT_Pi, 0.389825);
      normalize(_h_dpT_Piplus, 0.396025);
      normalize(_h_dpT_Kaon, 0.03897);
      normalize(_h_dpT_Kaonplus, 0.04046);
      normalize(_h_dpT_AntiProton, 0.0187255);
      normalize(_h_dpT_Proton, 0.016511);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_dNch;
    Histo1DPtr _h_dpT_Pi, _h_dpT_Piplus;
    Histo1DPtr _h_dpT_Kaon, _h_dpT_Kaonplus;
    Histo1DPtr _h_dpT_AntiProton, _h_dpT_Proton;
    Profile1DPtr _h_pT_vs_Nch;
    //CounterPtr nCutsPassed, nPi, nPiPlus, nKaon, nKaonPlus, nProton, nAntiProton;
    ///@}
  };


  RIVET_DECLARE_ALIASED_PLUGIN(STAR_2008_I793126, STAR_2008_S7869363);

}