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 ${\mathrm{\Theta }}^{+}$ mass. Known magnetic transition moments ${\mu }_{\mathrm{\Lambda }\mathrm{\Sigma }}$, ${\mu }_{N\mathrm{\Delta }}$ are reproduced and predictions for other octet-decuplet and octet-antidecuplet transitions are given. In particular ${\mu }_{\mathrm{\Sigma }{\mathrm{\Sigma }}^{\ast }}$ 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 neutron-like resonance.