N∗ electroproduction amplitudes in a model with dynamical confinement

The Roper resonance is described in a chiral version of the chromodielectric model as a cluster of three quarks in radial–orbital configuration (1s)2(2s)1, surrounded by π- and σ-meson clouds and by a chromodielectric field which assures quark dynamical confinement. Radial profiles for all fields are determined self-consistently for each baryon. Transverse A1/2 and scalar S1/2 helicity amplitudes for the nucleon–Roper transition are calculated. The contribution of glueball and σ-meson vibrations is estimated; although small for N(1440), the σ contribution can be large for N(1710).