EPJ Web of Conferences 282, 01001 (2023)
https://doi.org/10.1051/epjconf/202328201001

Lepton Flavor Universality at Belle and Belle II

Iowa State University and High Energy Accelerator Research Organization

^* e-mail: seema.choudhury@kek.jp

Published online: 3 April 2023

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⁺ν_ℓ decay, exclusive measurement of ℛ(D) & ℛ(D^*) in Belle data, and inclusive ℛ(X_e/µ) in Belle II. For the b → s transitions, we provide measurements of R_K and R_K^* 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⁺ν_ℓ decay using 922 fb⁻¹ of data collected by the Belle detector.