Measurements of jet observables sensitive to $b$-quark fragmentation in $t\bar{t}$ events at the LHC with the ATLAS detector

Abstract

Several observables sensitive to the fragmentation of $b$-quarks into $b$-hadrons are measured using 36 fb${}^{-1}$ of $\sqrt{s}=13$ TeV proton-proton collision data collected with the ATLAS detector at the LHC. Jets containing $b$-hadrons are obtained from a sample of dileptonic $t\bar{t}$ events, and the associated set of charged-particle tracks is separated into those from the primary $pp$ interaction vertex and those from the displaced $b$-decay secondary vertex. This division is used to construct observables that characterize the longitudinal and transverse momentum distributions of the $b$-hadron within the jet. The measurements have been corrected for detector effects and provide a test of heavy-quark-fragmentation modeling at the LHC in a system where the top-quark decay products are color-connected to the proton beam remnants. The unfolded distributions are compared with the predictions of several modern Monte Carlo parton-shower generators and generator tunes, and a wide range of agreement with the data is observed, with $p$-values varying from $5\times 10^{-4}$ to 0.98. These measurements complement similar measurements from $e^{+}{e}^{-}$ collider experiments in which the $b$-quarks originate from a color-singlet $Z/{\gamma }^{\ast }$.

arXiv comment49 pages in total, author list starting page 33, 10 figures, 3 tables, published in PRD. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2017-19/

References in corpus (63)

• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• The anti-k_t jet clustering algorithm
• An Introduction to PYTHIA 8.2
• A Brief Introduction to PYTHIA 8.1
• FastJet user manual
• Parton distributions for the LHC
• New Generation of Parton Distributions with Uncertainties from Global QCD Analysis
• A New Method for Combining NLO QCD with Shower Monte Carlo Algorithms
• Matching NLO QCD computations with Parton Shower simulations: the POWHEG method
• Parton distributions for the LHC Run II
• New parton distributions for collider physics
• Event generation with SHERPA 1.1
• Herwig++ Physics and Manual
• Parton distributions with LHC data
• The ATLAS Simulation Infrastructure
• PDF4LHC recommendations for LHC Run II
• Parton distributions in the LHC era: MMHT 2014 PDFs
• The total top quark pair production cross-section at hadron colliders through O(alpha_S^4)
• Scattering Amplitudes with Open Loops
• Top++: a program for the calculation of the top-pair cross-section at hadron colliders
• Herwig 7.0 / Herwig++ 3.0 Release Note
• A Positive-Weight Next-to-Leading-Order Monte Carlo for Heavy Flavour Hadroproduction
• Comix, a new matrix element generator
• Tuning PYTHIA 8.1: the Monash 2013 Tune
• Tuning Monte Carlo Generators: The Perugia Tunes
• QCD matrix elements + parton showers: The NLO case
• Performance of the ATLAS Trigger System in 2015
• Single-top hadroproduction in association with a W boson
• The Catchment Area of Jets
• Percent level precision physics at the Tevatron: first genuine NNLO QCD corrections to q qbar -> t tbar + X
• Top-pair production at hadron colliders with next-to-next-to-leading logarithmic soft-gluon resummation
• FEWZ 2.0: A code for hadronic Z production at next-to-next-to-leading order
• Muon reconstruction performance of the ATLAS detector in proton--proton collision data at $\sqrt{s}$=13 TeV
• NNLO corrections to top-pair production at hadron colliders: the all-fermionic scattering channels
• NNLO corrections to top pair production at hadron colliders: the quark-gluon reaction
• Production and Integration of the ATLAS Insertable B-Layer
• The CT10 NNLO Global Analysis of QCD
• Performance of pile-up mitigation techniques for jets in $pp$ collisions at $\sqrt{s}=8$ TeV using the ATLAS detector
• Uncertainties on alpha_S in global PDF analyses and implications for predicted hadronic cross sections
• Towards Jetography
• Performance of $b$-Jet Identification in the ATLAS Experiment
• Jet energy scale measurements and their systematic uncertainties in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Performance of electron and photon triggers in ATLAS during LHC Run 2
• ATLAS data quality operations and performance for 2015-2018 data-taking
• Jet energy scale and resolution measured in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Performance of the ATLAS muon triggers in Run 2
• Calculation of Power Corrections to Hadronic Event Shapes
• Systematic event generator tuning for the LHC
• Electron reconstruction and identification in the ATLAS experiment using the 2015 and 2016 LHC proton-proton collision data at $\sqrt{s}$ = 13 TeV
• Study of the fragmentation of b quarks into B mesons at the Z peak
• Performance of the ATLAS Track Reconstruction Algorithms in Dense Environments in LHC Run 2
• Soft-Gluon Resummation for the Fragmentation of Light and Heavy Quarks at Large x
• Measurements of $b$-jet tagging efficiency with the ATLAS detector using $t\bar{t}$ events at $\sqrt{s}=13$ TeV
• Inclusive Analysis of the b Quark Fragmentation Function in Z Decays at LEP
• Measurement of the b-quark fragmentation function in Z0 decays
• Perturbative Heavy Quark Fragmentation Function through O(alpha_s^2)
• A Phenomenological Study of Heavy-Quark Fragmentation Functions in e+e- Annihilation
• A study of the b-quark fragmentation function with the DELPHI detector at LEP I and an averaged distribution obtained at the Z Pole
• Bottom Quark Fragmentation in Top Quark Decay
• Soft-Gluon Resummation for Bottom Fragmentation in Top Quark Decay
• Measurements of differential cross sections of top quark pair production in association with jets in $pp$ collisions at $\sqrt{s}=13$ TeV using the ATLAS detector
• Multi-jet merging in a variable flavor number scheme

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