Measurements of Branching Fractions and Time-Dependent CP-Violating Asymmetries in B→η′K Decays

We present measurements of the B → η ′ K branching fractions; for B + → η ′ K + we measure also the time-integrated charge asymmetry A ch , and for B 0 → η ′ K 0 S the time-dependent C P -violation parameters S and C . The data sample corresponds to 232 × 10 6 B ¯¯¯ B pairs produced by e + e − annihilation at the Υ ( 4 S ) . The results are B ( B → η ′ K + ) = ( 68.9 ± 2.0 ± 3.2 ) × 10 − 6 , B ( B 0 → η ′ K 0 ) = ( 67.4 ± 3.3 ± 3.2 ) × 10 − 6 , A ch = 0.033 ± 0.028 ± 0.005 , S = 0.30 ± 0.14 ± 0.02 , and C = − 0.21 ± 0.10 ± 0.02 , where the first error quoted is statistical and the second is systematic