The broad JP=0− meson in J/Ψ radiative decays

We consider all available data on radiative decays of J/Ψ to the JP=0− final states in ρρ, ωω, K∗K̄∗, φφ, ηππ, and κK; here κ refers to the Kπ S-wave. They are fitted to a single Breit–Wigner resonance having s-dependent widths proportional to the available phase space in each channel. This resonance has a K-matrix mass 2190±50 MeV and a full width at half maximum of 850±100 MeV; errors are mostly systematic. Decays are flavour-blind within errors, suggesting it is the 0− glueball predicted near this mass by lattice gauge calculations.