We measure the tau-to-light-lepton ratio of inclusive B-meson branching fractions R ( X tau= l ) equivalent to B ( B-* X tau nu ) = B ( B-* X l nu ) , 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 - 1 of electron-positron collision data collected with the Belle II detector. We find R ( X tau= l ) = 0.228 + 0.016(stat) ( stat ) + 0.036(syst), ( syst ) , in agreement with standard-model expectations. This is the first direct measurement of R ( X tau= l ) .

Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Aihara, H., Akopov, N., et al. (2024). First Measurement of R(Xτ/ℓ) as an Inclusive Test of the b→cτν Anomaly. PHYSICAL REVIEW LETTERS, 132(21), 211804-1-211804-8 [10.1103/physrevlett.132.211804].

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

Branchini, P.
Membro del Collaboration Group
;
Budano, A.
Membro del Collaboration Group
;
Bussino, S.
Membro del Collaboration Group
;
De Pietro, G.
Membro del Collaboration Group
;
Laurenza, M.
Membro del Collaboration Group
;
Martellini, C.
Membro del Collaboration Group
;
2024-01-01

Abstract

We measure the tau-to-light-lepton ratio of inclusive B-meson branching fractions R ( X tau= l ) equivalent to B ( B-* X tau nu ) = B ( B-* X l nu ) , 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 - 1 of electron-positron collision data collected with the Belle II detector. We find R ( X tau= l ) = 0.228 + 0.016(stat) ( stat ) + 0.036(syst), ( syst ) , in agreement with standard-model expectations. This is the first direct measurement of R ( X tau= l ) .
2024
Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Aihara, H., Akopov, N., et al. (2024). First Measurement of R(Xτ/ℓ) as an Inclusive Test of the b→cτν Anomaly. PHYSICAL REVIEW LETTERS, 132(21), 211804-1-211804-8 [10.1103/physrevlett.132.211804].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/480667
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