Rivet analyses

J/ψ production at 13 TeV

Experiment: LHCB (LHC)

Inspire ID: 1391511

Status: VALIDATED

Authors: - Peter Richardson

References: - JHEP 10 (2015) 172, 2015.

Beams: p+ p+

Beam energies: (6500.0, 6500.0)GeV

Run details: - J/psi production

Measurement of the double differential (in p_⟂ and y) cross section for J/ψ production at 13 TeV by the LHCB collaboration.

Source code:`LHCB_2015_I1391511.cc`

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

namespace Rivet {


  /// @brief  J/psi production at 13 TeV
  class LHCB_2015_I1391511 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2015_I1391511);


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

    /// Book histograms and initialise projections before the run
    void init() {
      declare(UnstableParticles(), "UFS");
      for(unsigned int ix=0;ix<3;++ix) {
        book(_h_Jpsi[ix],{2.0,2.5,3.0,3.5,4.0,4.5});
        for(unsigned int iy=0;iy<5;++iy) {
          if(ix<2)
            book(_h_Jpsi[ix]->bin(iy+1),1+ix,1,iy+1);
          else
            book(_h_Jpsi[ix]->bin(iy+1),"TMP/Jpsi_"+toString(iy),refData(3,1,iy+1));
    }
      }
      for(unsigned int ix=0;ix<2;++ix) {
    book(_h_pT[ix],4+ix,1,1);
    book(_h_y [ix],6+ix,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");
      // J/psi
      for (const Particle& p : ufs.particles(Cuts::pid==443)) {
    // prompt/non-prompt
    bool nonPrompt = p.fromBottom();
        double absrap = p.absrap();
        double xp = p.perp();
    if(absrap<2. || absrap>4.5 ||  xp>14.) continue;
    _h_Jpsi[nonPrompt]->fill(absrap,xp);
    _h_Jpsi[2        ]->fill(absrap,xp);
    _h_pT[nonPrompt  ]->fill(xp);
    _h_y [nonPrompt  ]->fill(absrap);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // 1/2 due rapidity folding +/-
      double factor = 0.5*crossSection()/nanobarn/sumOfWeights();
      for(unsigned int ix=0;ix<3;++ix) {
        scale(_h_Jpsi[ix],factor);
        divByGroupWidth(_h_Jpsi[ix]);
      }
      Estimate1DPtr tmp;
      for(unsigned int ix=0;ix<_h_Jpsi[1]->numBins();++ix) {
    book(tmp,3,1,1+ix);
    divide(_h_Jpsi[1]->bin(ix+1),_h_Jpsi[2]->bin(ix+1),tmp);
    tmp->scale(100.);
      }
      for(unsigned int ix=0;ix<2;++ix) {
    scale(_h_pT[ix],factor);
    scale(_h_y [ix],factor*1e-3);
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DGroupPtr _h_Jpsi[3];
    Histo1DPtr _h_pT[2],_h_y[2];
    /// @}


  };


  RIVET_DECLARE_PLUGIN(LHCB_2015_I1391511);

}

Rivet analyses

J/ψ production at 13 TeV

Source code:LHCB_2015_I1391511.cc

Source code:`LHCB_2015_I1391511.cc`