Transforming jet flavour tagging at ATLAS

Abstract

Jet flavour tagging enables the identification of jets originating from heavy-flavour quarks in proton-proton collisions at the Large Hadron Collider, playing a critical role in its physics programmes. This paper presents GN2, a transformer-based flavour tagging algorithm deployed by the ATLAS Collaboration that represents a different methodology compared to previous approaches. Designed to classify jets based on the flavour of their constituent particles, GN2 processes low-level tracking information in an end-to-end architecture and incorporates physics-informed auxiliary training objectives to enhance both interpretability and performance. Its performance is validated in both simulation and collision data. The measured c-jet (light-jet) rejection in data is improved by a factor of 3.5 (1.8) for a 70% b-jet tagging efficiency, compared to the previous algorithm. GN2 provides substantial benefits for physics analyses involving heavy-flavour jets, such as measurements of Higgs boson pair production and the couplings of bottom and charm quarks to the Higgs boson, and demonstrates the impact of advanced machine learning methods in experimental particle physics.

40 pages in total, author list starting page 23, 6 figures, 1 table, published in Nature Communications. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/FTAG-2023-05/

References in corpus (59)

• The anti-k_t jet clustering algorithm
• An Introduction to PYTHIA 8.2
• FastJet user manual
• A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX
• A New Method for Combining NLO QCD with Shower Monte Carlo Algorithms
• Matching NLO QCD computations with Parton Shower simulations: the POWHEG method
• Event generation with SHERPA 1.1
• Herwig++ Physics and Manual
• Parton distributions with LHC data
• The ATLAS Simulation Infrastructure
• Scattering Amplitudes with Open Loops
• Herwig 7.0 / Herwig++ 3.0 Release Note
• The Physics of Heavy Z' Gauge Bosons
• A parton shower algorithm based on Catani-Seymour dipole factorisation
• A Positive-Weight Next-to-Leading-Order Monte Carlo for Heavy Flavour Hadroproduction
• QCD Matrix Elements + Parton Showers
• Comix, a new matrix element generator
• Event Generation with Sherpa 2.2
• QCD matrix elements + parton showers: The NLO case
• QCD matrix elements and truncated showers
• Collier: a fortran-based Complex One-Loop LIbrary in Extended Regularizations
• Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV
• A critical appraisal of NLO+PS matching methods
• OpenLoops 2
• General-purpose event generators for LHC physics
• Performance of $b$-Jet Identification in the ATLAS Experiment
• ParticleNet: Jet Tagging via Particle Clouds
• ATLAS $b$-jet identification performance and efficiency measurement with $t\bar{t}$ events in $pp$ collisions at $\sqrt{s}=13$ TeV
• Jet reconstruction and performance using particle flow with the ATLAS Detector
• Observation of Higgs boson production in association with a top quark pair at the LHC with the ATLAS detector
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• Jet energy scale and resolution measured in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Observation of $H\to b\bar{b}$ decays and $VH$ production with the ATLAS detector
• Energy Flow Networks: Deep Sets for Particle Jets
• Jet Flavour Classification Using DeepJet
• Graph Neural Networks in Particle Physics
• Performance of the ATLAS Track Reconstruction Algorithms in Dense Environments in LHC Run 2
• ATLAS flavour-tagging algorithms for the LHC Run 2 $pp$ collision dataset
• Reconstruction of primary vertices at the ATLAS experiment in Run 1 proton-proton collisions at the LHC
• On Layer Normalization in the Transformer Architecture
• Measurement of the $c$-jet mistagging efficiency in $t\bar{t}$ events using $pp$ collision data at $\sqrt{s}=13$ TeV collected with the ATLAS detector
• Calibration of the light-flavour jet mistagging efficiency of the $b$-tagging algorithms with $Z$+jets events using 139 ${\mathrm{fb}}^{-1}$ of ATLAS proton-proton collision data at $\sqrt{s}=13$ TeV
• Software and computing for Run 3 of the ATLAS experiment at the LHC
• The ATLAS Experiment at the CERN Large Hadron Collider: A Description of the Detector Configuration for Run 3
• Measurement of the $\tau$-lepton lifetime at Belle
• Exploration at the high-energy frontier: ATLAS Run~2 searches investigating the exotic jungle beyond the Standard Model
• The quest to discover supersymmetry at the ATLAS experiment
• Pileup mitigation at the LHC: a theorist's view
• Measurement of the B^0 and B^+ meson lifetimes with fully reconstructed hadronic final states
• Software Performance of the ATLAS Track Reconstruction for LHC Run 3
• Measurements of $WH$ and $ZH$ production with Higgs boson decays into bottom quarks and direct constraints on the charm Yukawa coupling in $13\mathrm{TeV}$ $pp$ collisions with the ATLAS detector
• Characterising the Higgs boson with ATLAS data from Run 2 of the LHC
• Precise measurement of the $D^0$ and $D^{+}$ lifetimes at Belle II
• Electroweak, QCD and flavour physics studies with ATLAS data from Run 2 of the LHC
• Measurement of the ${\Lambda }_c^{+}$ lifetime
• Climbing to the Top of the ATLAS 13 TeV data
• Search for emerging jets in $pp$ collisions at $\sqrt{s}=13.6$ TeV with the ATLAS experiment
• Configuration, Performance, and Commissioning of the ATLAS $b$-jet Triggers for the 2022 and 2023 LHC data-taking periods
• Precision measurement of the $B^0$ meson lifetime using $B^0\to J/\psi K^{\ast 0}$ decays with the ATLAS detector

Cited by in corpus (3)

• Search for emerging jets in $pp$ collisions at $\sqrt{s}=13.6$ TeV with the ATLAS experiment
• Probing new physics in the Boosted $HH\to b\bar{b}\gamma \gamma$ channel at the LHC
• Octet scalars shaping LHC distributions in 4-jet final states