Improved measurements of branching fractions and CP asymmetries in B→ηh decays

We report improved measurements of B decays with an η meson in the final state using 492 fb-1 of data collected by the Belle detector at the KEKB e+e- collider. We observe the decays B±→ηπ± and B±→ηK± and measure the branching fractions B(B±→ηπ±)=(4.2±0.4(stat)±0.2(sys))x10-6 and B(B±→ηK±)=(1.9±0.3(stat)-0.1+0.2(sys))x10-6. The corresponding CP-violating asymmetries are measured to be -0.23±0.09(stat)±0.02(sys) for ηπ± and -0.39±0.16(stat)±0.03(sys) for ηK±. We also search for B0→ηK0 decays and set an upper limit of 1.9x10-6 at the 90% confidence level