Rivet analyses

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

namespace Rivet {


  /// @brief J/psi production at 5.02 TeV
  class LHCB_2021_I1915030 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2021_I1915030);


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

    /// Book histograms and initialise projections before the run
    void init() {
      declare(UnstableParticles(), "UFS");
      // histograms
      for (int ix = 0; ix < 3; ++ix) {
        book(_h_JPsi[ix], {2.0, 2.5, 3.0, 3.5, 4.0, 4.5});
        for (int iy = 0; iy < 5; ++iy) {
          if (ix < 2)
            book(_h_JPsi[ix]->bin(iy + 1), ix + 1, 1, iy + 1);
          else
            book(_h_JPsi[ix]->bin(iy + 1), "TMP/JPsi_" + toString(iy), refData(1, 1, iy + 1));
        }
      }
      book(_h_JPsi_pT[0], 3, 1, 1);
      book(_h_JPsi_pT[1], 4, 1, 1);
      book(_h_JPsi_y[0], 5, 1, 1);
      book(_h_JPsi_y[2], 5, 1, 2);
      book(_h_JPsi_y[1], 6, 1, 1);
    }


    /// 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(Cuts::pid == 443)) {
        // prompt/non-prompt
        bool nonPrompt = p.fromBottom();
        double absrap = p.absrap();
        double xp = p.perp();
        _h_JPsi[nonPrompt]->fill(absrap, xp);
        _h_JPsi[2]->fill(absrap, xp);
        if (absrap > 2. && absrap < 4.5) _h_JPsi_pT[nonPrompt]->fill(xp);
        if (xp < 14.) _h_JPsi_y[nonPrompt]->fill(absrap);
        if (xp < 8. && !nonPrompt) _h_JPsi_y[2]->fill(absrap);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // factor of 2 due rapidity +/-
      double factor = 0.5 * crossSection() / nanobarn / sumOfWeights();
      for (unsigned int ix = 0; ix < 3; ++ix) {
        scale(_h_JPsi[ix], factor);
        divByGroupWidth(_h_JPsi[ix]);
        scale(_h_JPsi_y[ix], factor);
        if (ix < 2) scale(_h_JPsi_pT[ix], factor);
      }
      for (unsigned int iy = 0; iy < _h_JPsi[0]->numBins(); ++iy) {
        // non-prompt J/psi percentage
        Estimate1DPtr tmp;
        book(tmp, 7, 1, iy + 1);
        efficiency(_h_JPsi[1]->bin(iy + 1), _h_JPsi[2]->bin(iy + 1), tmp);
        tmp->scale(100.);
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DGroupPtr _h_JPsi[3];
    Histo1DPtr _h_JPsi_pT[2], _h_JPsi_y[3];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(LHCB_2021_I1915030);

}