: We measure the tau-to-light-lepton ratio of inclusive B-meson branching fractions R(X_{τ/ℓ})≡B(B→Xτν)/B(B→Xℓν), where ℓ indicates an electron or muon, and thereby test the universality of charged-current weak interactions. We select events that have one fully reconstructed B meson and a charged lepton candidate from 189  fb^{-1} of electron-positron collision data collected with the Belle II detector. We find R(X_{τ/ℓ})=0.228±0.016(stat)±0.036(syst), in agreement with standard-model expectations. This is the first direct measurement of R(X_{τ/ℓ}).

First Measurement of R(Xτ/ℓ) as an Inclusive Test of the b→cτν Anomaly / Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Aihara, H., Akopov, N., Aloisio, A., Asner, D. M., Atmacan, H., Aushev, T., Aushev, V., Aversano, M., Babu, V., Bahinipati, S., Bambade, P., Banerjee, Sw., Bansal, S., Barrett, M., Baudot, J., Baur, A., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 132/2024:21(2024), pp. 211804.1-211804.8. [10.1103/physrevlett.132.211804]

First Measurement of R(Xτ/ℓ) as an Inclusive Test of the b→cτν Anomaly

Ganiev, E.;Ghosh, D.;Lanceri, L.;Manfredi, R.;Mantovano, M.;Raiz, S.;Vitale, L.;
2024-01-01

Abstract

: We measure the tau-to-light-lepton ratio of inclusive B-meson branching fractions R(X_{τ/ℓ})≡B(B→Xτν)/B(B→Xℓν), where ℓ indicates an electron or muon, and thereby test the universality of charged-current weak interactions. We select events that have one fully reconstructed B meson and a charged lepton candidate from 189  fb^{-1} of electron-positron collision data collected with the Belle II detector. We find R(X_{τ/ℓ})=0.228±0.016(stat)±0.036(syst), in agreement with standard-model expectations. This is the first direct measurement of R(X_{τ/ℓ}).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/3097968
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