Possible explanation of ϱ0ϱ0 production in J ψ radiative decay

The ρ{variant}⁰ρ{variant}⁰ production in the recent Mark II experiment of J/ψ radiative decay is interpreted as due to two isoscalar 2⁺⁺ four-quark (q²q²) states which together with the isotensor 2⁺⁺ four-quark state are responsible for the major part of the ρ{variant}⁰ρ{variant}⁰ enhancement observed in γγ→ρ{variant}⁰ρ{variant}⁰. It is believed to be different from the θ (1640) meson, a glueball candidate, which decays to ηη and kk. In order to distinguish between them, we propose to measure the angular correlation between γ and ρ{variant}⁰ in e⁺e^-→J/ψ→γρ{variant}⁰ρ{variant}⁰ and the branching ratio of the decay mode J/ψ→γωω. The 2⁺⁺ φφ resonance (at 2.16 GeV) observed in hadronic reactions is predicted to be produced in J/ψ radiative decay also with BR(J/ψ→γφφ)/BR(J/ψ→ γρ{variant}⁰ρ{variant}⁰)∼0.18.