Rivet analyses

Differential cross sections for Υ(1, 2, 3S) production at 7 TeV

Experiment: LHCB (LHC)

Inspire ID: 1091071

Status: VALIDATED

Authors: - Peter Richardson

References: - JHEP 06 (2013) 064

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - hadronic events with Upsilon production

Measurement of the double differential (in p⟂ and y) cross section for Υ(1, 2, 3S) production at 7 TeV by the LHCB collaboration.

Source code:LHCB_2012_I1091071.cc

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

namespace Rivet {


  /// @brief Upslion production at 7 TeV
  class LHCB_2012_I1091071 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2012_I1091071);


    /// @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_Ups[ix], {2.0, 2.5, 3.0, 3.5, 4.0, 4.5});
        for (unsigned int iy = 0; iy < 5; ++iy) {
          book(_h_Ups[ix]->bin(1 + iy), 2 + iy + 5 * ix, 1, 1);
        }
        book(_h_Ups_pT[ix], "TMP/Ups_" + toString(ix), refData(17, 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");
      // upsilon
      for (const Particle& p :
           ufs.particles(Cuts::pid == 553 or Cuts::pid == 100553 or Cuts::pid == 200553)) {
        double absrap = p.absrap();
        double xp = p.perp();
        if (absrap < 2. || absrap > 4.5) continue;
        unsigned int iups = p.pid() / 100000;
        _h_Ups_pT[iups]->fill(xp);
        _h_Ups[iups]->fill(absrap, xp);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // 1/2 due rapidity folding +/-
      double factor = 0.5 * crossSection() / picobarn / sumOfWeights();
      // branching ratios for upsilon
      vector<double> br = {0.0248, 0.0193, 0.0218};
      for (unsigned int ix = 0; ix < 3; ++ix) {
        scale(_h_Ups_pT[ix], factor * br[ix]);
        scale(_h_Ups[ix], factor * br[ix]);
        divByGroupWidth(_h_Ups[ix]);
      }
      for (unsigned int ix = 0; ix < 2; ++ix) {
        Estimate1DPtr tmp;
        book(tmp, 17, 1, 1 + ix);
        divide(_h_Ups_pT[ix + 1], _h_Ups_pT[0], tmp);
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_Ups_pT[3];
    Histo1DGroupPtr _h_Ups[3];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(LHCB_2012_I1091071);

}