Rivet analyses

B meson production at 7 TeV

Experiment: LHCB (LHC)

Inspire ID: 1238809

Status: VALIDATED

Authors: - Peter Richardson

References: - JHEP 08 (2013) 117

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - hadronic events with B meson

Measurement of the double differential (in p_⟂ and y) cross section for B meson production at 7 TeV by the LHCb collaboration.

Source code:`LHCB_2013_I1238809.cc`

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

namespace Rivet {


  /// @brief B meson production at 7 TeV
  class LHCB_2013_I1238809 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2013_I1238809);


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

    /// Book histograms and initialise projections before the run
    void init() {
      declare(UnstableParticles(), "UFS");
      for (unsigned int ib = 0; ib < 3; ++ib) {
        book(_h_sigma[ib], 1, 1, 1 + ib);
        book(_h_pT[ib], 5 + ib, 1, 1);
        book(_h_y[ib], 8 + ib, 1, 1);
        book(_h_B[ib], {2.0, 2.5, 3.0, 3.5, 4.0, 4.5});
        for (unsigned int iy = 0; iy < 5; ++iy) {
          book(_h_B[ib]->bin(iy + 1), 2 + ib, 1, 1 + iy);
        }
      }
    }


    /// 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 == 511 or Cuts::pid == 521 or Cuts::pid == 531)) {
        double absrap = p.absrap();
        if (absrap < 2. || absrap > 4.5) continue;
        unsigned int ib = (p.pid() % 100) / 10 - 1;
        double pT = p.perp();
        if (pT > 40.) continue;
        _h_sigma[ib]->fill(round(sqrtS()));
        _h_B[ib]->fill(absrap, pT);
        _h_pT[ib]->fill(pT);
        _h_y[ib]->fill(absrap);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // 1/2 due rapidity folding +/-
      double factor = 0.5 * crossSection() / microbarn / sumOfWeights();
      for (unsigned int ib = 0; ib < 3; ++ib) {
        scale(_h_B[ib], factor);
        divByGroupWidth(_h_B[ib]);
        scale(_h_sigma[ib], factor);
        scale(_h_y[ib], factor);
        scale(_h_pT[ib], factor);
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<int> _h_sigma[3];
    Histo1DGroupPtr _h_B[3];
    Histo1DPtr _h_pT[3], _h_y[3];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(LHCB_2013_I1238809);

}

Rivet analyses

B meson production at 7 TeV

Source code:LHCB_2013_I1238809.cc

Source code:`LHCB_2013_I1238809.cc`