Search for third-generation vector-like leptons in $pp$ collisions at $\sqrt{s}=13\text{TeV}$ with the ATLAS detector

Abstract

A search for vector-like leptons in multilepton (two, three, or four-or-more electrons plus muons) final states with zero or more hadronic $\tau$-lepton decays is presented. The search is performed using a dataset corresponding to an integrated luminosity of 139 fb${}^{-1}$ of proton$-$proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the LHC. To maximize the separation of signal and background, a machine-learning classifier is used. No excess of events is observed beyond the Standard Model expectation. Using a doublet vector-like lepton model, vector-like leptons coupling to third-generation Standard Model leptons are excluded in the mass range from 130 GeV to 900 GeV at the 95% confidence level, while the highest excluded mass is expected to be 970 GeV.

arXiv comment48 pages, author list starting on page 29, 6 figures, 11 tables, published as JHEP 07 (2023) 118. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2020-07/

References in corpus (35)

• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• The anti-k_t jet clustering algorithm
• An Introduction to PYTHIA 8.2
• A Brief Introduction to PYTHIA 8.1
• FastJet user manual
• Asymptotic formulae for likelihood-based tests of new physics
• 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
• Parton distributions for the LHC Run II
• Parton distributions with LHC data
• A Supersymmetry Primer
• PDF4LHC recommendations for LHC Run II
• Dispelling the N^3 myth for the Kt jet-finder
• Scattering Amplitudes with Open Loops
• A parton shower algorithm based on Catani-Seymour dipole factorisation
• 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
• Single-top hadroproduction in association with a W boson
• A critical appraisal of NLO+PS matching methods
• OpenLoops 2
• Quarks and Leptons Beyond the Third Generation
• Gauge leptoquark as the origin of B-physics anomalies
• A modified cluster-hadronization model
• Third Family Quark-Lepton Unification at the TeV Scale
• Impact of a Higgs boson at a mass of 126 GeV on the standard model with three and four fermion generations
• Maximal Flavour Violation: a Cabibbo mechanism for leptoquarks
• Vectorlike leptons at the Large Hadron Collider
• Sealing the fate of a fourth generation of fermions
• Reweighting QCD matrix-element and parton-shower calculations
• Prospects for vectorlike leptons at future proton-proton colliders

Cited by in corpus (10)

• Exploration at the high-energy frontier: ATLAS Run~2 searches investigating the exotic jungle beyond the Standard Model
• Global fit to $b\to c\tau \nu$ anomalies as of Spring 2024
• Global analysis and LHC study of a vector-like extension of the Standard Model with extra scalars
• Long-lived Searches of Vector-like Lepton and Its Accompanying Scalar at Colliders
• Stability of the Standard Model Vacuum with Vector-Like Leptons: A Critical Examination
• Muon $g-2$ Anomaly from Vector-like Leptons in a 2-Higgs-doublet + Scalar Singlet Model
• Collider imprint of vector-like leptons in light of anomalous magnetic moment and neutrino data
• Graph Reinforcement Learning for Exploring BSM Model Spaces
• Search for new physics in jet multiplicity patterns of multilepton events at $\sqrt{s}$ = 13 TeV
• Freeze-in Production of Non-Abelian Millicharged Vector Dark Matter