Power corrections in charmless B decays

Abstract

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 $B^{+}\to {\pi }^{+}{K}^{\ast 0}$ to that of $B^0\to {\pi }^{-}{\rho }^{+}$, 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 $B^0\to K^{-}{\rho }^{+}$ 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 $B\to {\pi }^{+}{\pi }^{-}$ to be about 3 times larger than that of $B\to {\pi }^{\pm }{K}^{\mp }$, with opposite sign. In particular, the large measured value for $B\to {\pi }^{\pm }{K}^{\mp }$ CP asymmetry implies naturally a corresponding large $B\to {\pi }^{+}{\pi }^{-}$ CP asymmetry as observed by Belle. Experimentally any significant deviation from this prediction or possibly the importance of long-distance rescattering effects.

Talk given at the QCD Euroconference 2004, Montpellier 5-9 July 2004., LateX, 7 pages, 2 figures