Electromagnetic structure of light baryons in lattice QCD

A method for computing electromagnetic properties of hadrons in quenched lattice QCD is applied to the extraction of electromagnetic properties of the octet baryons. This allows a determination of the full dependence of the baryon masses on the charges and masses of the valence quarks. Results of a first numerical study (at β = 5.7 with Wilson action and light quark masses fixed from the pseudoscalar meson spectrum) are reported. The quenched octet baryon isomultiplet splittings (with statistical errors) are found to be: N − P = 2.08(±0.56), Σ0 − Σ+ = 2.63(±0.39), Σ− − Σ0 = 4.90(±0.36) and Ξ− − Ξ0 = 5.58(±0.24) MeV. Estimates of the systematic electromagnetic corrections arising from finite volume are included in these results.