Chiral Effects of Quenched η′ Loops

Preliminary results of a study of quenched chiral logarithms at beta = 5.7 are presented. Four independent determinations of the quenched chiral log parameter delta are obtained. Two of these are from estimates of the eta' mass, one from the residue of the hairpin diagram and the other from the topological susceptibility combined with the Witten-Veneziano formula. The other two determinations of delta are from measurement of virtual eta' loop effects in m(pi)(2) vs, quark mass and in the chiral behavior of the pseudoscalar decay constant. All of our results are consistent with delta = .080(15). The expected absence of quenched chiral logs in the axial-vector decay constant is also observed.