Andrea Fodor

29 October 2019

Abstract: The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is a substantial upgrade of the B factory facility, Belle, at the Japanese KEK laboratory. %The design luminosity of the machine is $8\times 10^{35}$ cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ of data, a factor of 50 more than its predecessor. The main operation of SuperKEKB has started in March 2019, and collisions ran until July 2019, achieving a peak luminosity of $5.5\times 10^{33}$ cm$^{-2}$s$^{-1}$. The results presented here were obtained from a subset of collected data of 0.41~fb$^{-1}$. In the poster presented at the conference the first results from studying semileptonic $\textit{B}$-meson decays were shown. The performance of the Full Event Interpretation (FEI) tagging was analysed. The $B^0 \rightarrow D^{*-} \ell^+ \nu_{\ell}$ mode was rediscovered, using the untagged approach.