The phenomenology of inclusive heavy-to-light sum rules

Abstract By calculating the O(αs) corrections to inclusive heavy-to-light sum rules we find model independent upper and lower bounds on form factors for B →πl ν and B →ρl ν . We use the bounds to rule out model predictions. Some models violate the bounds only for certain ranges of sum rule input parameters Λ ≃m B −m b and λ1, or for certain choices of model parameters, while others obey or violate the bounds irrespective of the inputs. We discuss the reliability and convergence of the bounds, point out their utility for extracting Vub, and derive from them a new form factor scaling relation.