qbar q Loop Effects on Baryon Masses

Corrections to the masses of baryons from baryon-meson loops are calculated using a pair-creation model to give the momentum-dependent vertices, and a model which includes configuration mixing to describe the wave functions of the baryons. A large set of baryon-meson intermediate states are employed, with all allowed SU(3)_f combinations, and excitations of the intermediate baryon states up to and including the second band of negative-parity excited states. It is found that roughly half of the splitting between the nucleon and Delta ground states arises from loop effects, and the resulting splittings of negative-parity excited states are sensitive to configuration mixing caused by the residual interactions. With reduced-strength one-gluon-exchange interactions between the quarks, there is a reasonable correspondence between model masses and the bare masses required to fit the masses extracted from data analyses.