Observation of B Meson Decays to eta pi and eta K

Abstract

We present preliminary measurements of the B meson decays B+->etapi+, B+->etaK+, and B0->etaK0. The data were recorded with the BABAR detector at PEP II and correspond to 88.9 million BBbar pairs produced in e+e- annihilation through the Upsilon(4S) resonance. We find the branching fractions B(B+->etapi+) = (4.2 +1.0-0.9 +/- 0.3)x 10^-6 and B(B+->etaK+) = (2.8 +0.8-0.7 +/-0.2)x10^-6. We set a 90% CL upper limit of B(B0->etaK0) < 4.6x10^-6. The time-integrated charge asymmetries are Ach(B+->etapi+) = -0.51 +0.20-0.18 +/-0.01 and Ach(B+->etaK+) = -0.32 +0.22-0.18 +/-0.01.