Inclusive beauty decays and the spectator model

A complete updated analysis of the branching ratios of inclusive b decays in a pure parton picture with inert spectator light quark(s) is presented. In view of recent data that indicate a rather small value for the average semileptonic decay fraction, particular attention is devoted to evaluating the central value and the range of theoretical errors for this quantity. We find that, while the data are marginally consistent with the spectator model, there are perhaps indications for a moderate non-spectator contribution. We discuss possible terms of this kind and argue that the ratio τ-/τ0 should probably be around its present upper limit. (orig.)