Implications of Charmless B Decays with Large Direct CP Violation

Abstract

Based on the most recent data in charmless B decays including the very recently reported large direct CP violations, it is shown that the weak phase gamma can well be extracted without two-fold ambiguity even only from two decay modes pi^+pi^- and pi^+K^-, and its value is remarkably consistent with the global standard model fit at a compatible accuracy. A fit to all the pi pi, pi K data favor both large electroweak penguin and color-suppressed tree amplitude with large strong phases. It is demonstrated that the inclusion of small SU(3)symmetry breaking effects of strong phases and the inelastic rescattering effects can well improve the consistency of the data, while both effects may not be sufficient to arrive at a small electroweak penguin amplitude in the standard model. It is of interest to notice that large or small electroweak penguin amplitude becomes a testable prediction as they lead to significantly different predictions for the direct CP violations for pi^0 pi^0, pi^0 K^0 modes. Clearly, precise measurements on charmless B decays will provide a window for probing new physics.