Phenomenological consideration of six-quark states in few-nucleon systems

The authors discuss how the idea of existence of many-quark systems in nuclei has recently provoked a great interest in model taking account of the quark structure of hadrons at small distances. It is natural to divide the two-hadron-interaction range into internal and external ones. In the external range the quark hadron structure manifests itself weakly and that interaction can be described by an ordinary regular type local potential. In the internal range the interaction is defined by a complex structure of the particles, it is nonlocal and energy dependent. To describe this interaction one uses different models whose parameters can be found from the equality condition of logarithmic derivatives of the interior and exterior wave functions on the surface of radius β. At present these models are of interest due to their possibility to connect the hadron-hadron scattering amplitudes with the parameters characterizing the hadron quark structure. The P-matrix description proved to be especially successful for analyzing the hadron-hadron scattering