We present evidence for the radiative decay J/ψ→γωω with a branching fraction of (1.76±0.09±0.45)×${10}^{\mathrm{-}3}$. The ωω invariant-mass distribution peaks at 1.8 GeV/$c^2$, just above threshold. Analysis of angular correlations indicates that ωω system below 2 GeV/$c^2$ is predominantly pseudoscalar. Upper limits are presented for the branching fractions of ωω decays of the θ(1690), the $g_T$ states near 2.2 GeV/$c^2$, and the ${\eta }_c$.

• Received 15 July 1985

DOI:https://doi.org/10.1103/PhysRevLett.55.1723