N^* electroproduction amplitudes in a model with dynamical confinement

Abstract

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 $A_{1/2}$ and scalar $S_{1/2}$ 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).

12 pages, 6 figures, uses elsevier macros