Rivet analyses

D^*± production in jets

Experiment: ATLAS (LHC)

Inspire ID: 1082009

Status: VALIDATED

Authors: - Peter Richardson

References: - arXiv: 1112.4432

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - All flavours of quark and gluon jet production at 7 TeV

Measurement of D^*± meson production in jets from proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=7$ TeV at the LHC. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb⁻¹ for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |eta| < 2.5.

Source code:`ATLAS_2012_I1082009.cc`

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/IdentifiedFinalState.hh"
#include "Rivet/Projections/LeadingParticlesFinalState.hh"
#include "Rivet/Projections/MissingMomentum.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/VetoedFinalState.hh"

namespace Rivet {


  class ATLAS_2012_I1082009 : public Analysis {
  public:

    /// @name Constructors etc.
    /// @{

    /// Constructor
    ATLAS_2012_I1082009()
        : Analysis("ATLAS_2012_I1082009") { }

    /// @}


  public:

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

    /// Book histograms and initialise projections before the run
    void init() {

      // Input for the jets: No neutrinos, no muons
      VetoedFinalState veto;
      veto.addVetoPairId(PID::MUON);
      veto.vetoNeutrinos();
      FastJets jets(veto, JetAlg::ANTIKT, 0.6);
      declare(jets, "jets");
      // unstable final-state for D*
      declare(UnstableParticles(), "UFS");

      book(_weight25_30, "_weight_25_30");
      book(_weight30_40, "_weight_30_40");
      book(_weight40_50, "_weight_40_50");
      book(_weight50_60, "_weight_50_60");
      book(_weight60_70, "_weight_60_70");
      book(_weight25_70, "_weight_25_70");

      book(_h_pt25_30, 8, 1, 1);
      book(_h_pt30_40, 9, 1, 1);
      book(_h_pt40_50, 10, 1, 1);
      book(_h_pt50_60, 11, 1, 1);
      book(_h_pt60_70, 12, 1, 1);
      book(_h_pt25_70, 13, 1, 1);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // get the jets
      Jets jets = apply<FastJets>(event, "jets").jetsByPt(Cuts::pT > 25 * GeV && Cuts::abseta < 2.5);
      // get the D* mesons
      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
      Particles Dstar;
      for (const Particle& p : ufs.particles()) {
        const int id = p.abspid();
        if (id == 413) Dstar.push_back(p);
      }

      // loop over the jobs
      for (const Jet& jet : jets) {
        double perp = jet.perp();
        bool found = false;
        double z(0.);
        if (perp < 25. || perp > 70.) continue;
        for (const Particle& p : Dstar) {
          if (p.perp() < 7.5) continue;
          if (deltaR(p, jet.momentum()) < 0.6) {
            Vector3 axis = jet.p3().unit();
            z = axis.dot(p.p3()) / jet.E();
            if (z < 0.3) continue;
            found = true;
            break;
          }
        }
        _weight25_70->fill();
        if (found) _h_pt25_70->fill(z);
        if (perp >= 25. && perp < 30.) {
          _weight25_30->fill();
          if (found) _h_pt25_30->fill(z);
        }
        else if (perp >= 30. && perp < 40.) {
          _weight30_40->fill();
          if (found) _h_pt30_40->fill(z);
        }
        else if (perp >= 40. && perp < 50.) {
          _weight40_50->fill();
          if (found) _h_pt40_50->fill(z);
        }
        else if (perp >= 50. && perp < 60.) {
          _weight50_60->fill();
          if (found) _h_pt50_60->fill(z);
        }
        else if (perp >= 60. && perp < 70.) {
          _weight60_70->fill();
          if (found) _h_pt60_70->fill(z);
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h_pt25_30, 1. / *_weight25_30);
      scale(_h_pt30_40, 1. / *_weight30_40);
      scale(_h_pt40_50, 1. / *_weight40_50);
      scale(_h_pt50_60, 1. / *_weight50_60);
      scale(_h_pt60_70, 1. / *_weight60_70);
      scale(_h_pt25_70, 1. / *_weight25_70);
    }

    /// @}


  private:

    /// @name Histograms
    /// @{
    CounterPtr _weight25_30, _weight30_40, _weight40_50;
    CounterPtr _weight50_60, _weight60_70, _weight25_70;

    Histo1DPtr _h_pt25_30;
    Histo1DPtr _h_pt30_40;
    Histo1DPtr _h_pt40_50;
    Histo1DPtr _h_pt50_60;
    Histo1DPtr _h_pt60_70;
    Histo1DPtr _h_pt25_70;
    /// @}
  };

  RIVET_DECLARE_PLUGIN(ATLAS_2012_I1082009);

}

Rivet analyses

D*± production in jets

Source code:ATLAS_2012_I1082009.cc

D^*± production in jets

Source code:`ATLAS_2012_I1082009.cc`