ETA-ETA' PHOTOPRODUCTION AND THE AXIAL ISOSCALAR NEUTRAL-CURRENT COUPLING

We show that coherent eta and eta' photoproduction by means of the Pri makoff Effect on the proton depends on the strange component of the ne utral axial current coupling. We construct polarization asymmetries th at are sensitive to this coupling through the gamma-Z interference. Th e eta' is not a Goldstone boson of a spontaneously broken chiral symme try, but a phenomenological analysis of the eta and eta' production th rough chiral perturbation theory allows to calculate the observables o f interest. The polarized proton or polarized photon asym-metries are predicted to be close to 10(-4) for - q(2) similar to 0.1 - 0.5 GeV2.