THE N-ASTERISK(1520)-]DELTA-PI AMPLITUDES EXTRACTED FROM THE GAMMA-P-]PI(-)P REACTION AND COMPARISON TO QUARK MODELS()PI()

The gamma p --> pi(+)pi(-)p reaction, in combination with data from th e pi N --> pi pi N reaction has been recently analyzed and allows one to obtain the s- and d-wave amplitudes for the N(1520) decay into Del ta pi with absolute sign with respect to the N(1520) --> N gamma heli city amplitudes. In addition one obtains the novel information on the momentum dependence of the amplitudes. In the present paper we show ho w this new information poses new constraints to quark models of hadron structure. In particular we show that the signs and the momentum depe ndence of these amplitudes coincide with those given by non relativist ic constituent quark models. The absolute values provided by these mod els agree only qualitatively, and a discussion is done on the reasons for it and possible ways to improve.