Theoretical predictions of beauty hadron lifetimes, based on the heavy quarkexpansion up to and including order 1/mb^2, do not to reproduce theexperimental measurements of the lifetime ratios tau(B+)/tau(Bd) andtau(Lambdab)/tau(Bd). Large corrections to these predictions come fromphase-space enhanced 1/mb^3 contributions, i.e. hard spectator effects. In thispaper we calculate the next-to-leading order QCD corrections to the Wilsoncoefficients of the local operators appearing at O(1/mb^3). We find that thesecorrections improve the agreement with the experimental data. The lifetimeratio of charged to neutral B mesons, tau(B+)/tau(Bd), turns out to be in verygood agreement with the corresponding measurement, whereas for tau(Bs)/tau(Bd)and tau(Lambdab)/tau(Bd) there is a residual difference at the 1-sigma level.We discuss, however, why the theoretical predictions are less accurate in thelatter cases.
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