A simple π-η-gh′ mixing model for R= Γ (ψ′ → ψπ) Γ(ψ′ → ψη) and r = Γ(ψ → η′γ) Γ(ψ → ηγ)

A joint description of the ratios r ≡ Γ(ψ → η′γ) Γ(ψ → ηγ) and R ≡ Γ(ψ′ → ψ π) Γ(ψ′ → ψη) is achieved in the context of a simple π-η-gh′ mixing model. An η-η′ mixing angle θ {reversed tilde equals} - 19.5° and a large tadpole effect for the ηπ and η′π isospinviolating transitions are required. Both requirements are in agreement with recent data for the η-meson. © 1984.