Tests of Light-Lepton Universality in Angular Asymmetries of B0→D*−ℓν Decays

We present the first comprehensive tests of the universality of the light leptons in the angular distributions of semileptonic B0-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay recoil that are sensitive to lepton-universality-violating contributions. We use events where one neutral B is fully reconstructed in ϒ(4S)→BB¯ decays in data corresponding to 189 fb−1 integrated luminosity from electron-positron collisions collected with the Belle II detector. We find no significant deviation from the standard model expectations.Received 9 August 2023Accepted 29 September 2023DOI:https://doi.org/10.1103/PhysRevLett.131.181801Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasElectroweak interactionLeptonic, semileptonic & radiative decaysW & Z bosonsPhysical SystemsBottom mesonsPropertiesFlavor symmetriesTechniquesLepton collidersParticles & Fields