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 pi- and sigma -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 A(1/2) and scalar S-1/2 helicity amplitudes for the nucleon-Roper transition are calculated. The contribution of glueball and alpha -meson vibrations is estimated; although small for N( 1440), the sigma contribution can be large for N(1710). (C) 2001 Elsevier Science B.V. All rights reserved.