Inclusive B-c decays as a QCD lab

Phenomenological models of heavy flavour decays differ significantly in their predictions of global features of B-c decays, like the B-c lifetime or the relative weight of c --> s and b --> c transitions. The 1/m(Q) expansion which is directly based on QCD allows predictions on the pattern to be expected, namely tau(B-c) to lie well below 1 psec with c --> s dominating over b --> c. Due to interference effects one also predicts a lower charm content in the final states of B, decays than naively anticipated. The numerical aspect of the predictions, however, has to be viewed with considerable caution since one cannot expect the 1/m(c) expansion to converge readily for Delta C = 1 transitions.