[eta], [eta]' mixing and anomalies

Abstract

We discuss the effects of [eta], [eta]' mixing and of the gluon anomaly in the decays [eta]-->3[pi]0, [eta]'-->3[pi]0, [psi]-->[eta][gamma] and [psi]-->[eta]' [gamma]. These effects are particularly important for [eta]'-->3[pi]0 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 [eta], [eta]' mixing angle ([theta]) and a reasonable fit with experiment is obtained for -20[deg][les][theta][les]-16[deg].