Chiral Corrections to Baryon Electromagnetic Form Factors

Corrections motivated by chiral symmetry arguments have long been known to give important contributions to hadronic observables, particularly at low momentum transfer. It is possible to separate these approaches into two broad groups; either the corrections are implemented at the parton level, or at the hadron level. We explore the results of incorporating pion loop corrections at the hadron level to a calculation of electromagnetic form factors in the NJL model. These calculations are compared with the result of an earlier implementation of pion loops at the parton level using the same NJL model formalism. A particular parameter set yields a good description of low energy nucleon properties within both approaches. However, for the $\Sigma^-$ there is a remarkable improvement when the chiral corrections are implemented at the hadronic level.