We present the results of the re-discovery of the decay $B^0 to pi^- ell^+ u_ell$ in 34.6 fb$^{-1}$ of Belle II data using hadronic $B$-tagging via the Full Event Interpretation algorithm. We observe 21 signal events on a background of 155 in a fit to the distribution of the square of the missing mass, $M_{mathrm{miss}}^2$, with a significance of 5.69$sigma$, and determine a total branching fraction of (1.58 $pm$ 0.43$_{mathrm{stat}}$ $pm$ 0.07$_{mathrm{sys}}$) $times 10^{-4}$.
Download