A proposal to solve some puzzles in semileptonic B decays

Abstract

About 25% of all B mesons decay semileptonically via the tree-level b ? c quark transition and allow the precision determination of the Cabibbo-Kobayashi Maskawa matrix element |Vcb|. Although these decays were the major focus of both B-Factory experiments over the last decade, about 10% of the semileptonic remain poorly known what limits our understanding of rare decays, such as the semileptonic b ? u transitions. We investigate the possibility of a large contribution from radial excited states to the semileptonic branching fraction and discuss its consequences.