Electromagnetic Structure of Light Baryons in Lattice QCD

A method in which electromagnetic properties of hadrons are studied by direct simulation of dynamical photon effects is applied to the extraction of the isomultiplet structure of the octet baryons. Using 187 configurations at $\beta=5.7$ with Wilson action, and up and down quark masses determined from the meson spectrum, the nucleon splitting is found to be $1.55(\pm 0.56\; \rm stat)$ MeV; the hyperon splittings are found to be $\Sigma^{0}-\Sigma^{+}=2.47\pm 0.39$, $\Sigma^{-}-\Sigma^{0}=4.63\pm 0.36$, $\Xi^{-}-\Xi^{0}=5.68\pm 0.24$ MeV. Estimated systematic corrections arising from finite volume and the quenched approximation are included in these results.