Rivet analyses

J/ψ production at 2.76 TeV

Experiment: ALICE (LHC)

Inspire ID: 1094079

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett.B 718 (2012) 295-306

Beams: p+ p+

Beam energies: (1380.0, 1380.0)GeV

Run details: - J/psi production in pp

Measurement of J/ψ production in the forward region by ALICE at 2.76 TeV. The rate in the central region is also measured, but not the differential cross section.

Source code:ALICE_2012_I1094079.cc

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

namespace Rivet {


  /// @brief J/psi production at 2.76 TeV
  class ALICE_2012_I1094079 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(ALICE_2012_I1094079);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projection
      declare(UnstableParticles(Cuts::pid == 443), "UFS");
      // histos
      book(_h_pT,1,1,1);
      book(_h_y ,4,1,1);
    }


    /// 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 on pT and rapidity
        double y = p.absrap();
        if (y>2.5 && y<4.) {
          _h_pT->fill(p.perp());
        }
        _h_y->fill(p.rap());
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      double factor = crossSection() / microbarn/ sumOfWeights();
      scale(_h_pT,factor/3.);
      scale(_h_y ,factor);
    }

    ///@}


    /// @name Histograms
    ///@{
    Histo1DPtr _h_pT,_h_y;
    ///@}


  };


  RIVET_DECLARE_PLUGIN(ALICE_2012_I1094079);

}