A search for charged lepton flavour violation in t ? 3 µ decays is performed in pp collisions at a centre-of-mass energy of 13 TeV using ATLAS data collected between 2016 and 2018, corresponding to an integrated luminosity of 137 fb-1. The search is optimised for the electroweak W ? t? production channel, due to its higher trigger efficiency, but also considers potential signal events from heavy-flavour production. Data are collected using two-muon and three-muon triggers and a multivariate analysis is used to separate the signal from the background. An unbinned likelihood fit is then performed to the resulting three-muon invariant mass spectrum and the data are found to be compatible with the background-only hypothesis. The observed (expected) limit on the branching ratio B (t ? 3 µ) is found to be 8.7×10-8 (7.5×10-8) at 90% CL

Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.J., et al. (2026). A search for lepton-flavour violating τ → 3μ decays with the ATLAS detector. PHYSICS LETTERS. SECTION B, 880 [10.1016/j.physletb.2026.140748].

A search for lepton-flavour violating τ → 3μ decays with the ATLAS detector

Di Micco, B.;Di Nardo, R.;Montereali, F.;Orestano, D.;Orlandini, R.;
2026-01-01

Abstract

A search for charged lepton flavour violation in t ? 3 µ decays is performed in pp collisions at a centre-of-mass energy of 13 TeV using ATLAS data collected between 2016 and 2018, corresponding to an integrated luminosity of 137 fb-1. The search is optimised for the electroweak W ? t? production channel, due to its higher trigger efficiency, but also considers potential signal events from heavy-flavour production. Data are collected using two-muon and three-muon triggers and a multivariate analysis is used to separate the signal from the background. An unbinned likelihood fit is then performed to the resulting three-muon invariant mass spectrum and the data are found to be compatible with the background-only hypothesis. The observed (expected) limit on the branching ratio B (t ? 3 µ) is found to be 8.7×10-8 (7.5×10-8) at 90% CL
2026
Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.J., et al. (2026). A search for lepton-flavour violating τ → 3μ decays with the ATLAS detector. PHYSICS LETTERS. SECTION B, 880 [10.1016/j.physletb.2026.140748].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/561277
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