Rivet analyses

Prompt Ds + /Ds− Asymmetry at 7 and 8 TeV

Experiment: LHCB (LHC)

Inspire ID: 1674916

Status: VALIDATED

Authors: - Peter Richardson

References: - JHEP 08 (2018) 008, 2018

Beams: p+ p+

Beam energies: (3500.0, 3500.0); (4000.0, 4000.0)GeV

Run details: - D_s production

Measurement of the production asymmetry for prompt Ds + /Ds− at 7 and 8 TeV by LHCb.

Source code:LHCB_2018_I1674916.cc

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

namespace Rivet {


  /// @brief D_s asymmetry
  class LHCB_2018_I1674916 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2018_I1674916);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projection
      declare(UnstableParticles(), "UFS");

      for (double eVal : allowedEnergies()) {
        const int en = int(eVal + 0.5);
        if (isCompatibleWithSqrtS(eVal)) _sqs = en;

        for (size_t ix = 0; ix < 2; ++ix) {
          book(_h[en + ix], {2., 3., 3.5, 4.5});
          for (auto& b : _h[en + ix]->bins()) {
            book(b, "TMP/h_" + toString(ix + 1) + "_" + toString(b.index()) + "_" + toString(en),
                 refData(2, 1, b.index()));
          }
        }
      }
      raiseBeamErrorIf(_sqs == 0);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
      for (const Particle& p : ufs.particles(Cuts::abspid == 431)) {
        if (p.fromBottom()) continue;
        const double pT = p.perp();
        const double y = p.absrap();
        const bool anti = p.pid() < 0;
        _h[_sqs + anti]->fill(y, pT);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {

      for (double eVal : allowedEnergies()) {
        const int en = int(eVal + 0.5);
        int ih = 2 + (en == 8000);
        // asymmetry
        Estimate1DPtr tmp;
        for (const auto& b : _h[en + 0]->bins()) {
          book(tmp, ih, 1, b.index());
          asymm(b, _h[en + 1]->bin(b.index()), tmp);
        }
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    map<int, Histo1DGroupPtr> _h;
    int _sqs = 0;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(LHCB_2018_I1674916);

}