On the origin of the short range NN repulsion

We calculate S-wave singlet and tripler NN phase shifts stemming from the s hort-range flavor-spin hyperfine interaction between constituent quarks usi ng the resonating group method approach. A strong short-range repulsion is found in both waves. A fair comparison is performed between the traditional picture, relying on the colour-magnetic interaction, and the present one, relying on the Goldstone boson exchange dynamics. It is shown that the latt er one induces essentially stronger repulsion, which is a very welcome feat ure. We also study a sensitivity of phase shifts and wave function to exten sion from the one-channel to three-channel resonating group method approxim ation. (C) 2000 Elsevier Science B.V. Ail rights reserved.