New results on semileptonic $B$ decays from the Belle experiment

Abstract

This proceeding summarizes the recent measurements of semileptonic $b\to u$ decays from the Belle experiment. These analyses use the full data set collected at the $\Upsilon(4S)$ resonance at KEKB accelerator complex with a center-of-mass energy of $\sqrt{s} = 10.58$ GeV, which contains an integrated luminosity of 711 fb$^{-1}$ and corresponds to 772 million $\Upsilon(4S) \to B\bar{B}$ events. In the sector of inclusive decay, the partial branching fraction of $B \to X_{u} \ell \nu$ decays and the CKM matrix element $|V_{ub}|$ are measured with hadronic tagging. The first measurement of differential branching fractions of $B \to X_{u} \ell \nu$ are shown as a function of different kinematic variables in this contribution as a preliminary result. For the exclusive mode, the branching fraction of $B^{+} \to \pi^{+}\pi^{-} \ell \nu$ including both resonant and non-resonant contributions is measured for the first time. The preliminary results on the branching fractions of $B^{+} \to \eta \ell \nu$ and $B^{+} \to \eta^{(\prime)} \ell \nu$ in the full $q^{2}$ range are also presented.