Hyperons with and without Doublet Symmetry

The object of this study is a system containing a baryon with the properties of the $\Lambda -\Sigma$ quartet, in strong interaction with mesons which may be bound to form various isobar states. The model involves two independent coupling constants $g$ and $g^{\prime }$. It will be shown that the case $g=g^{\prime }$ which corresponds to doublet (or global) symmetry is singular in that it is strongly affected by a certain quantum-mechanical resonance.