Rivet analyses

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

namespace Rivet {


  /// @brief chi_c production at 7 TeV
  class LHCB_2012_I1107645 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2012_I1107645);


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

    /// Book histograms and initialise projections before the run
    void init() {
      declare(UnstableParticles(), "UFS");
      for (unsigned int ix = 0; ix < 2; ++ix) {
        book(_h_pT[ix], "TMP/pT_" + toString(ix), refData(1, 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 || Cuts::pid == 10441 || Cuts::pid == 20443 || Cuts::pid == 445)) {
        // prompt only
        if (p.fromBottom()) continue;
        // J/psi as a reference
        if (p.pid() == 443) {
          double absrap = p.absrap();
          if (absrap > 2. && absrap < 4.5) _h_pT[1]->fill(p.perp());
        }
        else {
          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;
          double absrap = Jpsi.absrap();
          if (absrap < 2. || absrap > 4.5) continue;
          _h_pT[0]->fill(Jpsi.perp());
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // compute fraction
      Estimate1DPtr tmp;
      book(tmp, 1, 1, 1);
      efficiency(_h_pT[0], _h_pT[1], tmp);
    }

    /// @}


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


  RIVET_DECLARE_PLUGIN(LHCB_2012_I1107645);

}