Spectator effects and lifetimes of heavy hadrons

We present a calculation of subleading 1/mb corrections to spectator effects in the ratios of beauty hadron lifetimes in heavy-quark expansion. We find that these effects are sizable and should be taken into account in systematic analyses of heavy hadron lifetimes. In particular, the inclusion of 1/mb corrections brings into agreement the theoretical predictions and experimental observations of the ratio of lifetimes of Λb-baryon and Bd meson. We obtain τ(Bu)/τ(Bd) = 1.09± 0.03, τ(Bs)/τ(Bd) = 1.00 ± 0.01, τ(Λb)/τ(Bd) = 0.87 ± 0.05.