Observation of Exclusive Two-Body B Decays to Kaons and Pions

Abstract

We have studied two-body charmless hadronic decays of B mesons into the final states $ππ$, $K π$, and $KK$. Using 3.3 million $B\bar{B}$ pairs collected with the CLEO-II detector, we have made the first observation of the decays $B^0\to K^+π^-$, $B^+\to K^0π^+$, and the sum of $B^+ \to π^+π^0$ and $B^+ \to K^+π^0$ decays (an average over charge-conjugate states is always implied). We place upper limits on branching fractions for the remaining decay modes.