Chiral Effects of Quenched Eta-Prime Loops

Abstract

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-prime 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-prime loop effects in mpi^2 vs. quark mass and in the chiral behavior of the pseudoscalar decay constant. All results are consistent with delta=.080(15). The expected absence of quenched chiral logs in the axial-vector decay constant is also observed.