Implications of CP Asymmetry Limits for $B \to K \pi$ and $B \to \pi \pi$

Abstract

Recent experimental limits for the direct CP asymmetries in $B^0 \to K^+ \pi^-$, $B^+ \to K^+ \pi^0$, $B^+ \to K^0 \pi^+$, and $B^0 \to \pi^+ \pi^-$, and for the indirect CP asymmetry in $B^0 \to \pi^+ \pi^-$, are combined with information on CP-averaged branching ratios to shed light on weak and strong phases. At present such bounds favor $\gamma \ge 60^\circ$ at the $1 \sigma$ level. The prospects for further improvements are discussed.