Hyperon magnetic moments and the $1^{--}$→$0^{-+}$+$\gamma$ decays

Recent precision measurements of hyperon magnetic moments reveal that the moments of the $\Lambda$, ${\Sigma }^{+}$, and ${\Xi }^0$ are significantly smaller than the values predicted by the Coleman-Glashow formula or by the naive quark model. In the theoretical framework of SU(3) charge-current equal-time commutation relations and asymptotic SU(3) symmetry, the spin-nonflip sum rules imply that the usual SU(3) parametrization should apply not for the hyperon magnetic moments but for the product (anomalous magnetic moment)×(hyperon mass). Thus, the gross features of the observed hyperon magnetic moments are explained in terms of these derived mass-scale factors. The consistency of the spin-nonflip and -flip sum rules also implies that the remaining discrepancies should be attributed to the SU(3) mixings between the hyperons and their higher-lying excited ${\mathrm{½}}^{+}$ states. In the same theoretical framework, the status of the similar magnetic-moment interactions, $1^{--}$→$0^{-+}$+$\gamma$, is also reviewed, by studying the consistency of the asymptotic SU(3) sum rules. It is concluded that the usual consideration of the related SU(3) mixing, especially the ones involving the $\eta$ and ${\eta }^{\prime }$, is insufficient.