Symmetry relations for heavy-to-light meson form factors at large recoil

Abstract

The description of large-recoil heavy-to-light meson form factors is reviewed in the framework of soft-collinear effective theory. At leading power in the heavy-quark expansion, three classes of approximate symmetry relations arise. The relations are compared to experimental data for D → K* and Ds → φ form factors, and to light-cone QCD sum rule predictions for B → π and B → ρ form factors. Implications for the extraction of |Vub| from semileptonic B → ρ decays are discussed.