Speaker
Description
The desire for additional determinations of the CKM matrix element $V_{ub}$ and a long-standing 2-3$\sigma$ discrepancy between results from inclusive $B\to X_u$ and exclusive $B\to\pi$ processes motivate the study of $B\to\pi$ semileptonic form factors on the lattice. The status of our preliminary $B\to\pi\ell\nu$ results will be discussed by highlighting updates to our analysis. The analysis is carried out on a subset of the RBC/UKQCD 2+1f Iwasaki gauge action ensembles, with $b$ quarks simulated using the Columbia formulation of the relativistic heavy quark action, and the light valence-quarks simulated with domain wall fermions. We predict scalar and vector form factors over the entire range of allowed $q^2$ and use our results to test lepton universality $\textit{via}$ the R-ratio $\Gamma (B\to\pi\tau\nu) / \Gamma(B\to\pi\ell\nu)$, where $\ell$ in the denominator is either an electron or muon.
