Speaker
Description
With only 0.5% of the full projected $50\,\textrm{ab}^{-1}$ dataset, the Belle II detector is already a competitive high luminosity environment in which to study $B$ decays with missing energy. At a centre of mass energy of the $\Upsilon(4S)$ resonance, Belle II is a $B$ factory, producing approximately $1.1\times10^9$ $B\bar{B}$ pairs per $\textrm{ab}^{-1}$. Precise knowledge of one fully reconstructed $B$ meson through the hadronic Full Event Interpretation (FEI) tagging algorithm provides strong constraints for any signal decay studied using the other $B$ meson in the $B\bar{B}$ pair. In this talk, recent measurements of the signal decay $B\rightarrow D^{(*)}\ell \nu$ will be examined alongside the prospects of the $R(D)$ and $R(D^{*})$ measurements, in which Belle II anticipates a result of unprecedented precision with as little as $5\,\mbox{ab}^{-1}$ of data, and a sensitivity that could exhibit indirect New Physics effects.
