Search for long-lived particles using displaced vertices of oppositely charged leptons in 140 fb-1 of pp collisions at √s=13 TeV with the ATLAS detector



Aad, G, Aakvaag, E, Abbott, B, Abdelhameed, S, Abeling, K, Abicht, NJ, Abidi, SH, Aboelela, M, Aboulhorma, A, Abramowicz, H
et al (show 2863 more authors) (2026) Search for long-lived particles using displaced vertices of oppositely charged leptons in 140 fb-1 of pp collisions at √s=13 TeV with the ATLAS detector PHYSICS LETTERS B, 878. 140497-. ISSN 0370-2693, 1873-2445

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Abstract

A search is presented for long-lived particles decaying into an oppositely charged lepton pair, μ+μ−, e+e−, or e ± μ ∓, that form a vertex within the inner tracking system of the ATLAS detector at the Large Hadron Collider, displaced from the primary proton–proton interaction region. The analysis uses the 140 fb−1 of Run-2 data collected at s=13 TeV by the ATLAS experiment in 2015–2018. The results of the analysis are interpreted in the context of three benchmark models covering masses from 0.1 to 2.2 TeV and a range of mean proper lifetimes times the speed of light from 1 to 10 000 mm. The first model is a generic Z ′ boson pair-produced by a new heavy scalar, with the Z ′ decaying into lepton pairs. The remaining two models are R -parity violating supersymmetric models in which the lightest neutralino χ˜<inf>1</inf>0 decays into ℓ+ℓ′−ν (ℓ,ℓ′=e, μ). The models differ by the mode of production of the χ˜<inf>1</inf>0, which can be produced via the decay of pairs of gluinos or of pairs of charginos and neutralinos (χ˜<inf>1</inf>±χ˜<inf>1</inf>0, χ˜<inf>1</inf>±χ˜<inf>2</inf>0, or χ˜<inf>2</inf>0χ˜<inf>1</inf>0). Although each benchmark sample includes pair-produced LLPs, only a single vertex is required to be reconstructed. No dilepton displaced vertex candidate is observed and the results are presented as upper limits on the production cross-sections. This analysis sets leading limits on the production cross-sections for multiple models, including parameter space that has never been directly probed.

Item Type: Article
Uncontrolled Keywords: 5106 Nuclear and Plasma Physics, 5107 Particle and High Energy Physics, 51 Physical Sciences
Divisions: Faculty of Science & Engineering
Faculty of Science & Engineering > School of Physical Sciences
Faculty of Science & Engineering > School of Physical Sciences > Physics
Depositing User: Symplectic Admin
Date Deposited: 15 Jun 2026 14:13
Last Modified: 20 Jul 2026 13:27
DOI: 10.1016/j.physletb.2026.140497
Open Access URL: https://www.sciencedirect.com/science/article/pii/...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3198933
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