Possibility of a ninthJP=12+baryon. II

Abstract

We demonstrate that the hypothesis of asymptotic level realization of SU(3) in the algebra $[{A}_{i}, {A}_{j}]=i{f}_{\mathrm{ijk}}{V}_{k}$ added to the assumption that a ninth $I=0$, ${J}^{P}={\frac{1}{2}}^{+}$ baryon ${\ensuremath{\Lambda}}^{\ensuremath{'}}$ exists with a mass around 1700 MeV implies that deviations from the good results of SU(6) or SU(6) \ensuremath{\bigotimes} O(3) schemes can be derived theoretically, without invoking the notion of SU(6) symmetry. The Cabibbo angles are determined to be ${sin\ensuremath{\theta}}_{V}=0.227\ifmmode\pm\else\textpm\fi{}0.008$ and ${sin\ensuremath{\theta}}_{A}=0.224\ifmmode\pm\else\textpm\fi{}0.037$. We find that $\frac{D}{(D+F)}\ensuremath{\simeq}0.678$. Hyperon semileptonic decays in the presence of the ${\ensuremath{\Lambda}}^{\ensuremath{'}}$ are analyzed in detail. Partial widths for several ${\frac{3}{2}}^{+}\ensuremath{\rightarrow}{\frac{1}{2}}^{+}+\ensuremath{\pi}$ decays and branching ratios for the strong decay modes of the ${\ensuremath{\Lambda}}^{\ensuremath{'}}$ are discussed.