Physical Review D, vol.95, no.9, 2017 (SCI-Expanded)
Using (223.7±1.4)×106 J/ψ events accumulated with the BESIII detector, we study ηc decays to φφ and ωφ final states. The branching fraction of ηc→φφ is measured to be Br(ηc→φφ)=(2.5±0.3-0.7+0.3±0.6)×10-3, where the first uncertainty is statistical, the second is systematic, and the third is from the uncertainty of Br(J/ψ→γηc). No significant signal for the double Okubo-Zweig-Iizuka suppressed decay of ηc→ωφ is observed, and the upper limit on the branching fraction is determined to be Br(ηc→ωφ)<2.5×10-4 at the 90% confidence level.