ETA-ETA' GLUEBALL MIXING FROM PHOTON-MESON TRANSITION FORM-FACTORS AND THE DECAY RATIO D-S-]ETA-L-NU ETA'L-NU/

We have determined (a) the eta/eta' mixing angle and (b) the regions o f the allowed admixture of the glueball component with J(PC) = 0(-+) i n eta and eta', based on transition form factors eta --> gamma gamma and eta' --> gamma gamma at 0 less than or equal to Q(2) less than or equal to 20 GeV2/c(2), and the branching ratio D-s --> eta/nu/eta'l n u. For eta and eta' wave functions, eta = cos alpha (cos theta <n(n)ov er bar> -- sin theta <s(s)over bar>) + sin alpha G and eta' = cos alph a' (sin theta' <n(n)over bar> + cos theta' <s(s)over bar>) + sin alpha ' G where <n(n)over bar> = (<u(u)over bar> + dd)/root 2 and G means a glueball, a shape of the allowed region in the (theta, alpha, alpha') space is determined which is located inside the borders 0.56 less than or equal to sin theta less than or equal to 0.67, sin(2) alpha less t han or equal to 0.08, sin(2) alpha' less than or equal to 0.20. This c orresponds to theta(p) = -16.7 degrees +/- 2.8 degrees (90% confidence level). (C) 1997 Published by Elsevier Science B.V.