Dong, YB (reprint author), CCAST, World Lab, POB 8730, Beijing 100080, Peoples R China.
Based on a relativistic quark model approach, the transition properties of two positive-parity low-lying nucleon resonances Delta(1232) and Roper N(1440)p(11) and of Delta*(1600)P-33 resonance are investigated. The coupling constants gpiNN, gpiNDelta, gpiNN* and gpiNDelta* are also estimated. Two different ways to remove the center-of-mass motion are discussed. Our results of the relativistic approaches with and without the center-of-mass correction are compared to those of the nonrelativistic constituent quark model and to experimental data. Moreover, the effect of the pion cloud on the calculated observables is studied. Better results for the transition properties of the Delta(1232) resonance are obtained by taking the pion cloud into account explicitly. (C) 2002 Elsevier Science B.V. All rights reserved.