Implications of charmlessBdecays with large directCPviolation

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 $\ensuremath{\gamma}$ can well be extracted without twofold ambiguity even only from two decay modes ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and ${\ensuremath{\pi}}^{+}{K}^{\ensuremath{-}}$, and its value is remarkably consistent with the global standard model fit at a compatible accuracy. A fit to all the $\ensuremath{\pi}\ensuremath{\pi},\ensuremath{\pi}K$ data favor both large electroweak penguin and color-suppressed tree amplitude with large strong phases. It is demonstrated that the inclusion of $\mathrm{S}\mathrm{U}(3)$ 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 ${\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$, ${\ensuremath{\pi}}^{0}{\overline{K}}^{0}$ modes. Clearly, precise measurements on charmless $B$ decays will provide a window for probing new physics.