Semileptonicb→udecay

Abstract

The flaws and advantages of the different kinds of models for semileptonic $b\ensuremath{\rightarrow}u$ transitions are critically discussed. We argue that bound-state transition models are incomplete and should not be applied in phenomenological analyses of the electron end-point distribution. We describe a realistic model which corrects these deficiencies and combines the better features of the quark-decay models and the bound-state models.