Rivet analyses

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


namespace Rivet {


  /// @brief Xi_c0 at 5 TeV
  class ALICE_2021_I1863039 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(ALICE_2021_I1863039);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projection
      declare(UnstableParticles(Cuts::pid == 4132 || Cuts::pid == 421), "UFS");
      for (unsigned int ix = 0; ix < 2; ++ix) {
        book(_h_Xi_pT[ix], 1 + ix, 1, 1);
        book(_h_D0_pT[ix], "TMP/pT_D0_" + toString(ix), refData(3 + ix, 1, 1));
      }
      book(_h_Xi_pT[2], "TMP/pT_Xi", refData(4, 1, 1));
      book(_h_sig, 5, 1, 1);
      book(_c_D0, "TMP/c_D0");
      book(_c_Xi, "TMP/c_Xi");
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // Final state of unstable particles to get particle spectra
      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
      for (const Particle& p : ufs.particles()) {
        // no mixing
        if (p.children().size() == 1 || p.children()[0].abspid() == p.abspid()) continue;
        // rapidity cut
        if (p.absrap() > 0.5) continue;
        const double pT = p.perp();
        if (p.pid() == 421) {
          // only prompt
          if (!p.fromBottom()) {
            _h_D0_pT[0]->fill(pT);
            _h_D0_pT[1]->fill(pT);
          }
          _c_D0->fill();
        }
        else {
          // prompt
          if (!p.fromBottom()) {
            _c_Xi->fill();
            _h_sig->fill("$>$ 0.0"s);
            _h_Xi_pT[0]->fill(pT);
          }
          // inclusive
          _h_Xi_pT[1]->fill(pT);
          _h_Xi_pT[2]->fill(pT);
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      const double factor = crossSection() / microbarn / sumOfWeights();
      scale(_h_Xi_pT, factor);
      scale(_h_D0_pT, factor);
      scale(_h_sig, factor);

      // ratio prompt Xi0/D0
      Estimate1DPtr tmp;
      book(tmp, 3, 1, 1);
      divide(_h_Xi_pT[0], _h_D0_pT[0], tmp);

      // ratio  inclusive Xi0/D0
      book(tmp, 4, 1, 1);
      divide(_h_Xi_pT[2], _h_D0_pT[1], tmp);

      // ratio Xi0_D0 integrated
      Estimate0D e0d = *_c_Xi / *_c_D0;
      BinnedEstimatePtr<string> ratio;
      book(ratio, 6, 1, 1);
      auto& b = ratio->bin(1);
      b.setVal(e0d.val());
      b.setErr(e0d.err());
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_Xi_pT[3], _h_D0_pT[2];
    BinnedHistoPtr<string> _h_sig;
    CounterPtr _c_D0, _c_Xi;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(ALICE_2021_I1863039);

}