We report improved measurements of the partial rate asymmetry (${\mathcal{A}}_{CP}$) in $B\to hh$ decays with $140{\mathrm{f}\mathrm{b}}^{-1}$ of data collected with the Belle detector at the KEKB $e^{+}{e}^{-}$ collider. Here $h$ stands for a charged or neutral pion or kaon and in total five decay modes are included: $K^{\mp }{\pi }^{\pm }$, $K_S^0{\pi }^{\mp }$, $K^{\mp }{\pi }^0$, ${\pi }^{\mp }{\pi }^0$, and $K_S^0{\pi }^0$. The flavor of the last decay mode is determined from the accompanying $B$ meson. Using a data sample 4.7 times larger than that of our previous measurement, we find ${\mathcal{A}}_{CP}(K^{\mp }{\pi }^{\pm })-0.088\pm 0.035\pm 0.013$, $2.4\sigma$ from zero. Results for other decay modes are also presented.

• Received 14 July 2004

DOI:https://doi.org/10.1103/PhysRevD.71.031502