Lepton Flavor Universality at Belle and Belle II

Abstract

We report the test of lepton flavor universality at Belle and Belle II experiments considering b → c and b → s transitions. We use 711 fb−1 and 189 fb−1 of data collected at 𝒴(4S ) resonance from electron-positron collisions for Belle and Belle II, respectively. For the b → c transition, we present the measurement of lepton-flavor-universality in B0 → D*−ℓ+νℓ decay, exclusive measurement of ℛ(D) & ℛ(D*) in Belle data, and inclusive ℛ(Xe/µ) in Belle II. For the b → s transitions, we provide measurements of RK and RK* using Belle data, measurement of the branching fraction for the decay B → K*ℓℓ, and test of lepton-flavor-universality in B → J/ψK using Belle II data. Additionally, we report the lepton-flavor-universality in $ \Omega_{c}^{0} $ → Ω−ℓ+νℓ decay using 922 fb−1 of data collected by the Belle detector.