Electromagnetic structure of the proton and baryon spectrum in the nonrelativistic quark model

Abstract

The properties of the positive-parity ground-state baryons are analyzed in the nonrelativistic quark model using the hyperspherical harmonic expansion method to handle the dynamics of the three-quark system bound by a confinement potential. The usual contact term is made more flexible with an adjustable parameter to account for terms missing from the standard Fermi-Breit potential. The root-mean-square radius and charge form factor of the free proton are obtained and compared with experimental values. The reliability of the model is ascertained for the rms radius and charge form factor of the proton and the masses of the ground-state baryons. We also calculate the masses of the ${N}^{\mathrm{*}}$(1470), ${N}^{\mathrm{*}}$(1710), and ${\ensuremath{\Delta}}^{\mathrm{*}}$(1690) resonances.