Observation of B→η′K∗ and Evidence for B+→η′ρ+

Abstract

We present an observation of B → η ′ K ∗ . The data sample corresponds to 232 × 10 6 B ¯¯¯ B pairs collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the Stanford Linear Accelerator Center. We measure the branching fractions (in units of 10 − 6 ) B ( B 0 → η ′ K * 0 ) = 3.8 ± 1.1 ± 0.5 and B ( B + → η ′ K * + ) = 4.9 + 1.9 − 1.7 ± 0.8 , where the first error is statistical and the second systematic. A simultaneous fit results in the observation of B → η ′ K ∗ with B ( B → η ′ K ∗ ) = 4.1 + 1.0 − 0.9 ± 0.5 . We also search for B → η ′ ρ and η ′ f 0 ( 980 ) ( f 0 → π + π − ) with results and 90% confidence level upper limits B ( B + → η ′ ρ + ) = 8.7 + 3.1 + 2.3 − 2.8 − 1.3 ( < 14 ), B ( B 0 → η ′ ρ 0 ) < 3.7 , and B ( B 0 → η ′ f 0 ( 980 ) ( f 0 → π + π − ) ) < 1.5 . Charge asymmetries in the channels with significant yields are consistent with zero.