000000552 001__ 552 000000552 005__ 20170419004805.0 000000552 037__ $$aBELLE2-TALK-CONF-2017-040 000000552 041__ $$aeng 000000552 088__ $$aBELLE2-TALK-DRAFT-2017-008 000000552 100__ $$aMatic Lubej 000000552 245__ $$aDetermination of Vub at Belle II 000000552 260__ $$aMoriond EW 2017$$c2017-03-24 000000552 300__ $$amult. p 000000552 500__ $$a5' (3'+2') 9 actual slides + many backup slides 000000552 520__ $$aSemileptonic decays of $B$ mesons involving low-mass charged leptons $e$ or $\mu$ are expected to be free of non-Standard Model contributions and therefore play a critical role in determinations of $\vert V_{ub} \vert$ and $\vert V_{cb} \vert$. Of all the CKM matrix parameters, $\vert V_{ub} \vert$ is the least precise and in most need of additional studies in order to constrain the apex of the Unitarity Triangle even further. We focus on exclusive reconstruction of charmless semileptonic $B$ meson decay $B \to \pi \ell \nu$, and present prospects and estimates for $\vert V_{ub} \vert$ at Belle II with the full planned dataset of 50 ab$^{-1}$ of integrated luminosity. 000000552 6531_ $$acharmless 000000552 6531_ $$asemileptonic 000000552 6531_ $$avub 000000552 8560_ $$fdoris.yangsoo.kim@desy.de 000000552 8564_ $$uhttps://docs.belle2.org/record/552/files/BELLE2-TALK-CONF-2017-040.pdf