Roper electroproduction amplitudes in a chiral confinement model

A description of the Roper using the chiral chromodielectric model is presented and the transverse A1/2 and the scalar S1/2 helicity amplitudes for the electromagnetic Nucleon-Roper transition are obtained for small and moderate Q2. The sign of the amplitudes is correct but the model predictions underestimate the data at the photon point. Our results do not indicate a change of sign in any amplitudes up to Q2 - 1 GeV2. The contribution of the scalar meson excitations to the Roper electroproduction is taken into account but it turns out to be small in comparison with the quark contribution. However, it is argued that mesonic excitations may play a more prominent role in higher excited states. (author)