A search for an unexpected asymmetry in the production of <i>e</i><SUP>+</SUP>μ<SUP>-</SUP> and <i>e</i><SUP>-</SUP>μ<SUP>+</SUP> pairs in proton-proton collisions recorded by the ATLAS detector at √<i>s</i>=13 TeV



Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, Aboulhorma, A, Abramowicz, H, Abreu, H
et al (show 2891 more authors) (2022) A search for an unexpected asymmetry in the production of <i>e</i><SUP>+</SUP>μ<SUP>-</SUP> and <i>e</i><SUP>-</SUP>μ<SUP>+</SUP> pairs in proton-proton collisions recorded by the ATLAS detector at √<i>s</i>=13 TeV. PHYSICS LETTERS B, 830. 137106-.

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Abstract

This search, a type not previously performed at ATLAS, uses a comparison of the production cross sections for $e^+ \mu^-$ and $e^- \mu^+$ pairs to constrain physics processes beyond the Standard Model. It uses $139 \text{fb}^{-1}$ of proton$-$proton collision data recorded at $\sqrt{s} = 13$ TeV at the LHC. Targeting sources of new physics which prefer final states containing $e^{+}\mu^{-}$ to $e^{-}\mu^{+}$, the search contains two broad signal regions which are used to provide model-independent constraints on the ratio of cross sections at the 2% level. The search also has two special selections targeting supersymmetric models and leptoquark signatures. Observations using one of these selections are able to exclude, at 95% confidence level, singly produced smuons with masses up to 640 GeV in a model in which the only other light sparticle is a neutralino when the $R$-parity-violating coupling $\lambda'_{231}$ is close to unity. Observations using the other selection exclude scalar leptoquarks with masses below 1880 GeV when $g_{\text{1R}}^{eu}=g_{\text{1R}}^{\mu c}=1$, at 95% confidence level. The limit on the coupling reduces to $g_{\text{1R}}^{eu}=g_{\text{1R}}^{\mu c}=0.46$ for a mass of 1420 GeV.

Item Type: Article
Additional Information: 38 pages in total, author list starting page 22, 8 figures, 1 table, submitted to Physics Letters B. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2018-29/
Uncontrolled Keywords: hep-ex, hep-ex
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 12 May 2022 14:50
Last Modified: 17 Oct 2023 04:14
DOI: 10.1016/j.physletb.2022.137106
Open Access URL: https://www.sciencedirect.com/science/article/pii/...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3154683