Searches for B0 decays to ηK0, ηη, η′η′, ηϕ, and η′ϕ

Abstract

We search for B 0 meson decays into two-body combinations of K 0 , η , η ′ , and ϕ mesons in 324 × 10 6 B ¯¯¯ B pairs collected with the BABAR detector at the PEP-II asymmetric-energy e + e − collider at SLAC. We measure the following branching fractions (upper limits at 90% confidence level) in units of 10 − 6 : B ( B 0 → η K 0 ) = 1.8 + 0.7 − 0.6 ± 0.1 ( < 2.9 ) , B ( B 0 → η η ) = 1.1 + 0.5 − 0.4 ± 0.1 ( < 1.8 ) , B ( B 0 → η ϕ ) = 0.1 ± 0.2 ± 0.1 ( < 0.6 ) , B ( B 0 → η ′ ϕ ) = 0.2 + 0.4 − 0.3 ± 0.1 ( < 1.0 ) , and B ( B 0 → η ′ η ′ ) = 1.0 + 0.8 − 0.6 ± 0.1 ( < 2.4 ) , where the first error is statistical and the second systematic.