Rivet analyses

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

namespace Rivet {


  /// @brief chi_c production at 7 TeV
  class ATLAS_2014_I1292798 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2014_I1292798);


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

    /// Book histograms and initialise projections before the run
    void init() {
      declare(UnstableParticles(Cuts::pid == 443 || Cuts::pid == 20443 || Cuts::pid == 445), "UFS");
      for (unsigned int ichi = 0; ichi < 2; ++ichi) {
        for (unsigned int ipT = 0; ipT < 2; ++ipT) {
          for (unsigned int iprompt = 0; iprompt < 2; ++iprompt) {
            book(_h_pT[ichi][iprompt][ipT], 1 + ichi + 2 * iprompt + 4 * ipT, 1, 1);
          }
          book(_h_pT[ichi][2][ipT], "TMP/chi_" + toString(ichi) + "_" + toString(ipT),
               refData(1 + ichi + 4 * ipT, 1, 1));
        }
      }
      for (unsigned int iprompt = 0; iprompt < 2; ++iprompt) {
        for (unsigned int ifeed = 0; ifeed < 2; ++ifeed) {
          book(_h_Jpsi[iprompt][ifeed], "TMP/jpsi_" + toString(iprompt) + "_" + toString(ifeed),
               refData(9 + iprompt, 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()) {
        // prompt/non-prompt
        bool nonPrompt = p.fromBottom();
        // J/psi as a reference
        if (p.pid() == 443) {
          if (p.absrap() < 0.75) _h_Jpsi[nonPrompt][0]->fill(p.perp());
        }
        else if (p.children().size() == 2) {
          Particle Jpsi;
          if (p.children()[0].pid() == 22 && p.children()[1].pid() == 443) {
            Jpsi = p.children()[1];
          }
          else if (p.children()[1].pid() == 22 && p.children()[0].pid() == 443) {
            Jpsi = p.children()[0];
          }
          else
            continue;
          if (Jpsi.absrap() > 0.75) continue;
          unsigned int ichi = p.pid() == 20443 ? 0 : 1;
          _h_Jpsi[nonPrompt][1]->fill(Jpsi.perp());
          _h_pT[ichi][nonPrompt][0]->fill(Jpsi.perp());
          _h_pT[ichi][nonPrompt][1]->fill(p.perp());
          _h_pT[ichi][2][0]->fill(Jpsi.perp());
          _h_pT[ichi][2][1]->fill(p.perp());
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // J/psi -> mu+mu- branching ratio
      const double br = 0.05961;
      const double fact = br * crossSection() / picobarn / sumOfWeights();
      for (unsigned int iprompt = 0; iprompt < 3; ++iprompt) {
        for (unsigned int ichi = 0; ichi < 2; ++ichi) {
          for (unsigned int ipT = 0; ipT < 2; ++ipT) {
            scale(_h_pT[ichi][iprompt][ipT], fact);
          }
        }
      }
      for (unsigned int iprompt = 0; iprompt < 2; ++iprompt) {
        for (unsigned int ifeed = 0; ifeed < 2; ++ifeed) {
          scale(_h_Jpsi[iprompt][ifeed], fact);
        }
      }
      // Jpsi feed down prompt
      Estimate1DPtr tmp;
      book(tmp, 9, 1, 1);
      efficiency(_h_Jpsi[0][1], _h_Jpsi[0][0], tmp);
      // ratio prompt chi2/chi1
      book(tmp, 10, 1, 1);
      divide(_h_pT[1][0][0], _h_pT[0][0][0], tmp);
      // ratio non-prompt chi2/chi1
      book(tmp, 11, 1, 1);
      divide(_h_pT[1][1][0], _h_pT[0][1][0], tmp);
      // ratio non-prmopt chi1
      book(tmp, 12, 1, 1);
      divide(_h_pT[0][1][1], _h_pT[0][2][1], tmp);
      // ratio non-prmopt chi2
      book(tmp, 13, 1, 1);
      divide(_h_pT[1][1][1], _h_pT[1][2][1], tmp);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_pT[2][3][2], _h_Jpsi[2][2];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(ATLAS_2014_I1292798);

}