Rivet analyses

Quarkonium production at 13 TeV

Experiment: CMS (LHC)

Inspire ID: 1633431

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett.B 780 (2018) 251-272, 2018 - arXiv: 1710.11002 - Expt page: CMS-BPH-15-005

Beams: p+ p+

Beam energies: (6500.0, 6500.0)GeV

Run details: - quarkonium production in pp

Measurement of prompt J/ψ, ψ(2S), and Υ(1, 2, 3S) production at 13 TeV by the CMS collaboration. The transverse momentum spectra are measured in a numbver of rapidity intervals, together with the ratio of the production of the excited states to the J/ψ or Υ(1S).

Source code:CMS_2018_I1633431.cc

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

namespace Rivet {


  /// @brief Quarkonium prouction at 13 TeV
  class CMS_2018_I1633431 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2018_I1633431);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projection
      declare(UnstableParticles(), "UFS");
      // J/psi/psi(2s) histos
      for (unsigned int ix=1; ix<3; ++ix) {
        book(_h_onium[ix-1], {0.,0.3,0.6,0.9,1.2});
        for (unsigned int iy=1; iy<5; ++iy) {
          Histo1DPtr tmp;
          book(_h_onium[ix-1]->bin(iy), ix, 1, iy);
        }
        book(_h_total[ix-1], ix, 1, 5);
      }
      // Upsilon
      for (unsigned int ix=3; ix<6; ++ix) {
        book(_h_onium[ix-1], {0.,0.6,1.2});
        for (unsigned int iy=1; iy<3; ++iy) {
          book(_h_onium[ix-1]->bin(iy), ix, 1, iy);
        }
        book(_h_total[ix-1], ix, 1, 3);
      }
      // histos for ratios
      for (unsigned int ix=0; ix<5; ++ix) {
        if (ix<2) {
          book(_h_ratio[ix],"TMP/h_ratio_"+to_str(ix), refData(11,1,1));
        }
        else {
          book(_h_ratio[ix],"TMP/h_ratio_"+to_str(ix), refData(12,1,1));
        }
      }
    }


    /// 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");
      // loop over onium states
      for (const Particle& p : ufs.particles(Cuts::pid==553 or Cuts::pid==100553 or
                                              Cuts::pid==200553 or
                                              Cuts::pid==443 or Cuts::pid==100443)) {
        // cuts on pT and rapidity
        const double y = p.absrap();
        const double pT = p.perp();
        if (y>1.2 || pT<20.) continue;
        unsigned int itype(0);
        if (p.pid()==443)         itype=0;
        else if (p.pid()==100443) itype=1;
        else if (p.pid()==553)    itype=2;
        else if (p.pid()==100553) itype=3;
        else if (p.pid()==200553) itype=4;
        // for J/pis and psi(2s) check if prompt
        if (itype<=1 && p.fromBottom()) continue;
        _h_onium[itype]->fill(y,pT);
        _h_total[itype]->fill(pT);
        _h_ratio[itype]->fill(pT);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // 0.5 due folded rapidity
      const double factor = 0.5*crossSection() / picobarn/ sumOfWeights();
      // branching ratios to muons
      const vector<double> brs={0.05961,0.00793,0.0248,0.0191,0.0218};
      for (unsigned int ix=0; ix<5; ++ix) {
        scale(_h_onium[ix], factor * brs[ix]);
        divByGroupWidth(_h_onium[ix]);
        scale(_h_total[ix],brs[ix]*factor/1.2);
        scale(_h_ratio[ix],brs[ix]*factor/1.2);
      }
      // ratio plots
      Estimate1DPtr tmp;
      book(tmp, 11, 1, 1);
      divide(_h_ratio[1], _h_ratio[0], tmp);
      for (unsigned int ix=0; ix<2; ++ix) {
        book(tmp,12,1,1+ix);
        divide(_h_ratio[3+ix], _h_ratio[2], tmp);
      }
    }

    ///@}


    /// @name Histograms
    ///@{
    Histo1DGroupPtr _h_onium[5];
    Histo1DPtr _h_total[5];
    Histo1DPtr _h_ratio[5];
    ///@}


  };


  RIVET_DECLARE_PLUGIN(CMS_2018_I1633431);

}