Precise test of lepton flavour universality in W-boson decays into muons and electrons in 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 2845 more authors) (2024) Precise test of lepton flavour universality in W-boson decays into muons and electrons in pp collisions at √s=13 TeV with the ATLAS detector EUROPEAN PHYSICAL JOURNAL C, 84 (10). 993-. ISSN 1434-6044, 1434-6052

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Abstract

The ratio of branching ratios of the W boson to muons and electrons, R<inf>W</inf>μ/e=B(W→μν)/B(W→eν), has been measured using 140fb-1 of pp collision data at s=13 TeV collected with the ATLAS detector at the LHC, probing the universality of lepton couplings. The ratio is obtained from measurements of the tt¯ production cross-section in the ee, eμ and μμ dilepton final states. To reduce systematic uncertainties, it is normalised by the square root of the corresponding ratio R<inf>Z</inf>μμ/ee for the Z boson measured in inclusive Z→ee and Z→μμ events. By using the precise value of R<inf>Z</inf>μμ/ee determined from e+e- colliders, the ratio R<inf>W</inf>μ/e is determined to be (Formula presented.) The three uncertainties correspond to data statistics, experimental systematics and the external measurement of R<inf>Z</inf>μμ/ee, giving a total uncertainty of 0.0045, and confirming the Standard Model assumption of lepton flavour universality in W-boson decays at the 0.5% level.

Item Type: Article
Uncontrolled Keywords: 5106 Nuclear and Plasma Physics, 5107 Particle and High Energy Physics, 51 Physical Sciences
Divisions: Faculty of Health & Life Sciences
Faculty of Science & Engineering
Faculty of Science & Engineering > School of Physical Sciences
Faculty of Health & Life Sciences > Inst. Systems, Molec & Integrative Biology > Inst. Systems, Molec & Integrative Biology
Depositing User: Symplectic Admin
Date Deposited: 28 Oct 2024 09:52
Last Modified: 23 May 2026 09:21
DOI: 10.1140/epjc/s10052-024-13070-4
Open Access URL: https://link.springer.com/article/10.1140/epjc/s10...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3186263
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