Exotic and nonexotic magnetic transitions in the context of the SELEX and GRAAL experiments

We calculate magnetic transition moments in the chiral quark-soliton model, with explicit SU(3)-symmetry breaking taken into account. The dynamical model parameters are fixed by experimental data for the magnetic moments of the baryon octet and from the recent measurements of ${\Theta }^{+}$ mass. Known magnetic transition moments ${\mu }_{\Lambda \Sigma }$, ${\mu }_{N\Delta }$ are reproduced and predictions for other octet-decuplet and octet-antidecuplet transitions are given. In particular ${\mu }_{\Sigma {\Sigma }^{*}}$ recently constrained by SELEX is shown to be below $0.82{\mu }_N$. The recent GRAAL data on $\eta$ photoproduction off the nucleon are explained in terms of a new narrow antidecuplet neutronlike resonance.

Figure 1

$\Delta \to N$ transition magnetic moment as function of ${\Sigma }_{\pi N}$ in the left panel and $\Sigma \to \Lambda$ one as function of ${\Sigma }_{\pi N}$ in the right panel.

Figure 2

${\Sigma }^{*-}\to {\Sigma }^{-}$ transition magnetic moment as functions of ${\Sigma }_{\pi N}$ in the left panel and ${\Sigma }^{*+}\to {\Sigma }^{+}$ one as functions of ${\Sigma }_{\pi N}$ in the right panel.

Figure 3

${\Xi }^{*0}\to {\Xi }^0$ transition magnetic moment as functions of ${\Sigma }_{\pi N}$ in the left panel and ${\Xi }^{*-}\to {\Xi }^{-}$ one as functions of ${\Sigma }_{\pi N}$ in the right panel.

Figure 4

${\Sigma }^{*0}\to \Lambda$ transition magnetic moment as functions of ${\Sigma }_{\pi N}$.

Figure 5

$p^{*}\to p$ transition magnetic moment as functions of ${\Sigma }_{\pi N}$ in the left panel and $n^{*}\to n$ one as functions of ${\Sigma }_{\pi N}$ in the right panel.