NN scattering phase shifts in a chiral constituent quark model

We study the nucleon-nucleon interaction within a chiral constituent quark model which reproduces successfully the baryon spectra. We calculate the S- 3(1) and S-1(0) phase shifts by using the resonating group method. They cle arly indicate the presence of a strong repulsive interaction at short dista nce, due to the spin-flavour symmetry of the quark-quark interaction and of the quark interchange between the two interacting nucleons. A sigma -meson exchange quark-quark interaction, providing a medium-range attraction, hel ps to get closer to the experimental phase shifts. (C) 2001 Elsevier Scienc e B,V, All rights reserved.