Radiative decays as tests of the symmetries of the Ψ particles

The success of the Okubo-Iizuka-Zweig rule for decays of Ψ and Ψ′ suggests that the radiative decays Ψ → γ + hadrons should be dominated by intermediates like Ψ → Ψ′ hadrons. This mechanism is consistent with experimental data which show Γ(Ψ → ?⁰π⁰) and Γ(Ψ → ηγ) to be comparable. if all Ψ-like particles are isoscalar, $\text{Γ(Ψ →}{}^0\text{γ)}$ should be very small. If all Ψ-like particles are SU(3) singlets, Γ(Ψ → η′γ)/Γ(Ψ → ηγ) should be large. Substantial violation of our predictions would be circumstantial evidence for the existence of non-singlet new quarks.