Power corrections in charmless B decays

Power corrections seem to play an important role in charmless B decays as indicated by recent analysis using QCD Factorization. In this talk, I would like to report on a recent work on power corrections in charmless B decays. By using the ratio of the branching fraction of B + → π + K *0 to that of B 0 → π − ρ + , for which the theoretical uncertainties are greatly reduced, it is shown in a transparent manner that power corrections in charmless B decays are probably large and that the B 0 → K − ρ + decay could be explained with the annihilation term included. For ratios of direct CP asymmetries, QCD Factorisation with the annihilation terms included would predict the direct CP asymmetry of B → π + π − to be about 3 times larger than that of B → π ± K -+ , with opposite sign. In particular, the large measured value for B → π ± K -+ , CP asymmetry implies naturally a corresponding large B → π + π − CP asymmetry as observed by Belle. Experimentally any significant deviation from this prediction would suggest either new physics or possibly the importance of long-distance rescattering effects.