Quark model baryon interactions and few particle system physics

Decay width of the pentaquark state which was found recently is discussed on the basis of the constituent quark model. Then the recent progress of the SU6 quark model of baryon interactions and its application to Faddeev calculation of few baryon systems are overviewed. The study of baryon-baryon interactions by SU6 quark model and the resonating group model are based on the simple three quark structure, which has the advantages that the experimentally well known nucleon-nucleon forces, the nucleon-hyperon (NY) and hyperon-hyperon (YY) interactions can be treated in the same framework without uncertainty by properly treating the fundamental color freedom and the quark antisymmetrization. The SU6 models of fss2 and FSS are the approaches to decide all baryon-baryon interactions of the baryon octet in consistency with experiments. In order to use those baryon interactions for Faddeev calculation of the few particle systems it is required to take into account both the energy dependence of the non-local interactions characteristic of the resonating group model and the existence of Pauli exclusion state in quark level. It has been shown by many cases that these considerations are properly performed so far as bound states are concerned. (S. Funahashi)