Systematic study of longitudinal and transverse helicity amplitudes in the hypercentral constituent quark model

We report in a systematic way the predictions of the nonrelativistic hypercentral constituent quark model for the electromagnetic excitations of baryon resonances. The longitudinal and transverse helicity amplitudes are calculated with no free parameters for fourteen resonances, for both protons and neutrons. The calculations lead to an overall fair description of data, especially in the medium-Q(2) range, where quark degrees of freedom are expected to dominate.