The ratio of branching ratios of the W boson to muons and electrons, R μ/e W = B(W → μν)/B(W → eν), has been measured using 140 fb−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 crosssection 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 μμ/ee Z for the Z boson measured in inclusive Z → ee and Z → μμ events. By using the precise value of R μμ/ee Z determined from e+e− colliders, the ratio R μ/e W is determined to be R μ/e W = 0.9995 ± 0.0022 (stat) ± 0.0036 (syst) ± 0.0014 (ext). The three uncertainties correspond to data statistics, experimental systematics and the external measurement of R μμ/ee Z , giving a total uncertainty of 0.0045, and confirming the Standard Model assumption of lepton flavour universality in Wboson decays at the 0.5% level.

Null, N., Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., et al. (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, PARTICLES AND FIELDS, 84(10), 1-33 [10.1140/epjc/s10052-024-13070-4].

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

Alberghi, G. L.;Alfonsi, F.;Ballabene, E.;Bellagamba, L.;Bianco, G.;Boscherini, D.;Bruni, A.;Carratta, G.;Corchia, F. A.;Cremonini, D.;De Castro, S.;Fabbri, F.;Fabbri, L.;Franchini, M.;Gabrielli, A.;Giacobbe, B.;Levrini, G.;Nechaeva, S.;Polini, A.;Rinaldi, L.;Romano, M.;Sanzani, E.;Sbarra, C.;Sbrizzi, A.;Semprini-Cesari, N.;Sioli, M.;Todome, K.;Valentinetti, S.;Villa, M.;Vittori, C.;Vivarelli, I.;Zoccoli, A.;
2024

Abstract

The ratio of branching ratios of the W boson to muons and electrons, R μ/e W = B(W → μν)/B(W → eν), has been measured using 140 fb−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 crosssection 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 μμ/ee Z for the Z boson measured in inclusive Z → ee and Z → μμ events. By using the precise value of R μμ/ee Z determined from e+e− colliders, the ratio R μ/e W is determined to be R μ/e W = 0.9995 ± 0.0022 (stat) ± 0.0036 (syst) ± 0.0014 (ext). The three uncertainties correspond to data statistics, experimental systematics and the external measurement of R μμ/ee Z , giving a total uncertainty of 0.0045, and confirming the Standard Model assumption of lepton flavour universality in Wboson decays at the 0.5% level.
2024
Null, N., Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., et al. (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, PARTICLES AND FIELDS, 84(10), 1-33 [10.1140/epjc/s10052-024-13070-4].
Null, Null; Aad, G.; Aakvaag, E.; Abbott, B.; Abdelhameed, S.; Abeling, K.; Abicht, N. J.; Abidi, S. H.; Aboelela, M.; Aboulhorma, A.; Abramowicz, H.;...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/1008084
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