Semileptonic $B \to ρ$ and $B \to π$ Decays: Lattice and Dispersive Constraints

Abstract

I present two recent pieces of work on semileptonic $B \to π, ρ$ decays where it is shown how lattice QCD calculations can be used to test heavy-quark symmetry and determine phenomenologically relevant quantities despite the limits on these calculations' kinematical reach. The study of semileptonic $B \to ρ$ decays was performed with the UKQCD Collaboration.