Search for direct CP violation in B→Kπ decays

We search for direct CP violation in flavor specific B → Kπ decays by measuring the rate asymmetry between charge conjugate modes. The search is performed on a data sample of 11.1 × 10⁶ BB events recorded on the Y(4S) resonance by the Belle experiment at KEKB. We measure 90% confidence intervals in the partial rate asymmetry A_CP of -0.25<A_CP(K^∓π^±)<0.37, -0.40<A_CP(K^∓π⁰)<0.36, and -0.53 <A _CP (K⁰π^∓)<0.82. By combining the K^∓π^± and K^∓π⁰ final states, we conclude that -0.22 <A_CP(K^∓(π^± + π⁰))<0.25 at the 90% confidence level.