Neutral meson photoproduction in SUf(3) chiral perturbation theory: γN-->π0N

We present the results for the electric dipole amplitude for γN-->π⁰N at threshold at the O(p²) level in SU_f(3) chiral perturbation theory. We find that the SU_f(3) results differ only slightly from the SU_f(2) results. At the O(p³) level one encounters new, unknown counterterms to fix which one is likely to need the threshold photoproduction data themselves, thus, losing predictive power. We suggest, instead, that the difference between the proton and neutron π⁰ photoproduction amplitudes may provide a test of the convergence properties of χPT in the present context. We urge that the neutron's electric dipole amplitude be measured.