Pentaquarks: Review on models and solitonic calculations of antidecuplet magnetic moments

After a quick look at the present status of experiments we briefly review in a first step the ongoing discussions on some of the basic theoretical approaches to pentaquarks: Chiral solitons, large-Nc considerations, quark models, and lattice gauge approaches. In a second step we apply the chiral quark-soliton approach including linear ms-corrections to the calculation of magnetic moments of the baryons of the antidecuplet. In this approach the parameters are fixed solely by experimental data for the magnetic moments of the baryon octet and for the masses of the octet, decuplet and of Θ+. The magnetic moment of Θ+ depends rather strongly on the pion-nucleon sigma term and reads −1.19 to −0.33 nm for ΣπN=45 and 75 MeV respectively. As a by-product the strange magnetic moment of the nucleon is obtained with a value of μN(s)=+0.39nm.