Baryon Resonances as Orbital Excitations of the Baryons

Abstract

A simple model of the baryon resonances is proposed in which internal spin-unitary-spin wave functions, belonging to a 56 of $\mathrm{SU}\left(6\right)\mathrm{}$, are coupled to internal orbital angular momentum. It is found that fourteen of the known baryon resonances may be accommodated in this scheme with maximal alignment of $L$ and $S$. Decays of the resonances are described in the model by an $\mathrm{SU}{\mathrm{}\left(6\right)\mathrm{}}_W$-invariant coupling to the meson 35, with fitted phenomenological parameters representing the effects of internal structure. The agreement with experimental total and partial widths is reasonably good. Of special interest is the fact that consistency of the model calls for the assignment of $J^P={\frac{5}{2}}^{-}$ to the ${\Xi }^{*}\mathrm{}\left(1933\right)\mathrm{}$, instead of ${\frac{5}{2}}^{+}$ as is usually assumed.