Electroexcitation of the Roper resonance in relativistic quark models

The amplitudes of the transition gamma N-*-> P-11(1440) are calculated within light-front relativistic quark model assuming that the P-11(1440) is the first radial excitation of the 3q ground state. The results are presented along with the predictions obtained in other relativistic quark models. In comparison with the previous calculations, we have extended the range of Q(2) up to 4.5 GeV2 to cover the kinematic interval of the forthcoming experimental data. Using approach based on the hypothesis of partially conserved axial-vector current, we checked the relative sign between quark model predictions for the N and P-11(1440) contributions to the pi electroproduction found in previous investigations.