Two-Body B Meson Decays to $\eta$ and ${\eta }^{{}^{\prime }}$ -- Observation of $B\to \eta${'}K$

CLEO Collaboration, B. Behrens et al

In a sample of 6.6 million produced B mesons we have observed decays B -> eta' K, with branching fractions BR(B+ -> eta' K+ = 6.5 +1.5 -1.4 +- 0.9) x $10^{-5}$ and BR(B0 -> eta' K0…