CP asymmetry in flavour-specific B decays

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I first discuss the phenomenology of aqfs (q=d,s), which is the CP asymmetry in flavour-specific Bq decays such as Bd -> X l+ nu-barₗ or Bₛ -> Dₛ- pi+. aqfs can be obtained from the time evolution of any untagged Bq decay. Then I present recently calculated next-to-leading-order QCD corrections to afsq, which reduce the renormalisation scheme uncertainties significantly. For the Standard Model we predict aᵈfs=-(5.0 +/- 1.1)*10(-4) and aˢfs= (2.1 +/-0.4)*10-5. As a by-product we determine the ratio of the width difference in the Bd system and the average Bd width to (Delta Gammad)/Gammad = (3.0 +/- 1.2)*10(-3) at next-to-leading order in QCD.