Lattice-Constrained Dispersive Bounds for $\bar B^0 \to \pi^+ l^-   \bar\nu$ Decays
  I present a recent piece of work on semileptonic $B \to \pi$ decays in which lattice results and kinematical and dispersive constraints are combined to obtain model-independent bounds on the relevant form factors and rates. 
Laurent Lellouch (CPT, Luminy)