PRD 85 (2012) 091102

Parameter	Measurement
\({\cal{B}} ( \bar{B}^0 \to J/\psi(1S) \eta )\)	\([12.3 ^{+1.8}_{-1.7}\mbox{ (stat)} \pm 0.7\mbox{ (syst)}] \times 10^{-6}\)
\({\cal{B}} ( \bar{B}^0 \to J/\psi(1S) \eta^\prime(958) )\)	\(7.4 \times 10^{-6}\)