The eta-eta' mixing angle and the relative radiative decay rates GAMMA(psi → eta γ)/GAMMA (psi → eta'γ)

The problem of eta-eta' mixing is reexamined within the nonet scheme. It is shown that the mixing angle thetasub(p) is quite sensitive to a small SU(3) violating 27 piece. Taking SU(3) violating qanti q annihilation terms into account, the author obtains large ratio GAMMA(psi → eta γ)/GAMMA (psi → eta'γ) which is largely independent of the mixing angle and agrees with the measured value to within 20-30%. (Auth.)