Latest results on semileptonic and electroweak penguin decays at Belle II

TL;DR

This paper reports recent measurements from Belle II on semileptonic B decays, including determinations of CKM matrix elements and branching fractions, using advanced analysis techniques with fully reconstructed and untagged methods.

Contribution

It introduces four new analyses of semileptonic and electroweak penguin B decays, providing updated measurements and methodologies at Belle II.

Findings

Precise measurement of V_{ub} from B→πeν decays.

Determination of V_{cb} from B→D*ℓν decays.

Branching fraction measurement of B→K*ℓ+ℓ− decays.

Abstract

The Belle~II Collaboration presents four new analyses: The measurement of $V_{ub}$ from $B \to \pi e \nu_e$ decays with a fit to the differential $q^2$ spectrum, the determination of $V_{cb}$ using a fit to the differential $w$ distribution from $B^0 \to D^{\ast -} \ell^+ \nu_\ell$ decays, and the measurement of $q^2$ moments in inclusive $B \to X_c \ell \nu_\ell$ decays. In all these analyses tag-side $B$ meson is reconstructed in a fully hadronic decay chain. The last result are branching fraction measurement of $B \to K^\ast \ell^+ \ell^-$ decays using an untagged approach.