Chiral perturbation theory and the magnetic moments of the baryon octet

Abstract

We have calculated, exactly to leading order in the chiral perturbation symmetry-breaking parameter $\ensuremath{\epsilon}$, the corrections to the Coleman-Glashow SU(3) relations a mong the magnetic moments of the baryon octet. The corrections are of order ${\ensuremath{\epsilon}}^{\frac{1}{2}}$. In general the corrections turn out to be at least as large as the zeroth-order term and hence the perturbation expansion breaks down. We discuss the reasons for this breakdown. We also derive sum rules which are independent of the leading-order corrections and hence valid to next order in chiral perturbation symmetry breaking, i.e., $\ensuremath{\epsilon}\mathrm{ln}\ensuremath{\epsilon}$.