Experimental study of \etac decays into vector-vector final states

Abstract

Using 58 million J/ψevents accumulated with the BES II detector, branching fractions for the η_{c} ->VV decays, η_{c} -> ρρ, η_{c} -> K^{*}{\bar K}^{*}, η_{c} -> ωω, and η_{c} -> ϕϕ, are measured. The branching fractions are Br(η_{c} -> ρρ) = (1.25 \pm 0.37 \pm 0.51) \times 10^{-2}, Br(η_{c} -> \K^{*}{\bar K}^{*}) = (10.4 \pm 2.6\pm 4.3) \times 10^{-3}, Br(η_{c} -> ωω) < 6.3 \times 10^{-3} (90 % CL), and Br(η_{c} -> ϕϕ) = (2.5 \pm 0.5 \pm 0.9) \times 10^{-3}. The process η_{c} -> ωϕis also searched for, and the 90% CL upper limit Br(eta_{c} -> ωϕ) < 1.3 \times 10^{-3} is obtained for this process.