Search for charged-lepton-flavour violation in <i>Z</i>-boson decays with the ATLAS detector



Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, Abou Zeid, OS, Abraham, NL, Abramowicz, H
et al (show 2927 more authors) (2021) Search for charged-lepton-flavour violation in <i>Z</i>-boson decays with the ATLAS detector. NATURE PHYSICS, 17 (7). 819-+.

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Abstract

A direct search for charged lepton-flavour violation in top-quark decays is presented. The data analysed correspond to $79.8\ \text{fb}^{-1}$ of proton--proton collisions at a centre-of-mass energy of $\sqrt{s}=13\ \text{TeV}$ recorded by the ATLAS experiment at the LHC. The process studied is the production of top-quark pairs, where one top quark decays into a pair of opposite-sign different-flavour charged leptons and an up-type quark, while the other decays semileptonically according to the Standard Model. The signature of the signal is thus characterised by the presence of three charged leptons, a light jet and a $b$-jet. A multivariate discriminant is deployed and its distribution used as input to extract the signal strength. In the absence of a signal, an upper limit on the branching ratio of ${\cal B}(t \to \ell \ell' q) < 1.86 \times 10^{-5}$ is set at the 95\% confidence level.

Item Type: Article
Additional Information: Proceedings for the 11th International Workshop on Top Quark Physics (TOP2018). 5 pages, 1 figure
Uncontrolled Keywords: hep-ex, hep-ex
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 22 Sep 2021 08:44
Last Modified: 11 Oct 2023 21:54
DOI: 10.1038/s41567-021-01225-z
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3137834