No abstract

The resonating group model is reformulated by splitting the microscopic interaction into a dominant part and a residual part. In the equal-width oscillator limit, the dominant part leads to a very simple exchange kernel. In norm kernel eigenstate representation, this kernel has a peculiar, fish bone like symmetry. For the evaluation of the residual interaction, only two-body matrix elements are needed. A physical interpretation of the fish bone symmetry is given in terms of the reflection property of a fermi sphere with a diffuse surface. An optical model is proposed in which the influence of partly Pauliforbidden states on the observables is described by the fish bone symmetry of the interaction. It is speculated that fish bone symmetry might be the key to a better understanding of hadronic interactions.Nuclear Reactions: Scattering theory, nuclear models, optical models, composite particle interaction, symmetry of interactions.

The resonating group interaction of three clusters, in the single channel no-distortion approximation, is split into a leading part and a residual part. In norm kernel eigenstate representation, the leading part exhibits a peculiar, fish bone like symmetry. An off-shell transformation, which leads to an energy-independent interaction, also reduces the strength of the three-body Pauli potential. The smallness of this potential is related to the possibility of interpreting cluster relative motion wave functions as probability density amplitudes. Neglecting all residual interactions and introducing, instead, fitting parameters into the two-cluster direct interactions leads to a three-cluster optical model, In this model the on-shell behaviour of two-cluster interactions is determined by experimental data, while their off-shell behaviour, as well as the three-cluster Pauli potential, are determined by the Pauli principle.Nuclear Reactions: Scattering theory, nuclear models, optical models, composite particle interactions, symmetry of interactions.