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

Abstract

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 $Θ^{+}$ mass. Known magnetic transition moments $μ_{ΛΣ}$, $μ_{NΔ}$ are reproduced and predictions for other octet-decuplet and octet-antidecuplet transitions are given. In particular $μ_{ΣΣ^{\ast}}$ recently constrained by SELEX is shown to be below $0.82 μ_N$. The recent GRAAL data on $η$ photoproduction off the nucleon are explained in terms of a new narrow antidecuplet neutron-like resonance.