η, η′ mixing and anomalies

Abstract

We discuss the effects of η, η′ mixing and of the gluon anomaly in the decays η→3π⁰, η′→3π⁰, ψ→ηγ and ψ→η′ γ. These effects are particularly important for η′→3π⁰ in reducing the total rate by about two orders of magnitude from the naive estimate. The decay rates are calculated for various values of the η, η′ mixing angle (θ) and a reasonable fit with experiment is obtained for −20°⩽θ⩽−16°.