ELECTROPRODUCTION OF THE ROPER RESONANCE AND THE CONSTITUENT QUARK-MODEL

A parameter-free evaluation of the N-P-11(1440) electromagnetic transi tion form factors is performed within a light-front constituent quark model, using for the first time the eigenfunctions of a mass operator which generates a large amount of configuration mixing in baryon wave functions. A one-body electromagnetic current, which includes the phen omenological constituent quark form factors already determined from an analysis of pion and nucleon experimental data, is adopted. For Q(2) up to few (GeV/c)(2), the effect of configuration mixing results in a significant suppression of the calculated helicity amplitudes with res pect to both relativistic and non-relativistic calculations, based on a simple gaussian-like ansatz for the baryon wave functions. (C) 1997 Published by Elsevier Science B.V.