Fits of the baryon magnetic moments to the quark model and spectrum-generating SU(3)

We show that for theoretical as well as phenomenological reasons the baryon magnetic moments that fulfill simple group transformation properties should be taken in intrinsic rather than nuclear magnetons. A fit of the recent experimental data to the reduced matrix elements of the usual octet electromagnetic current is still not good, and in order to obtain acceptable agreement, one has to add correction terms to the octet current. We have tested two kinds of corrections: $U$-spin-scalar terms, which are singled out by the model-independent algebraic properties of the hadron electromagnetic current, and octet $U$-spin vectors, which could come from quark-mass breaking in a nonrelativistic quark model. We find that the $U$-spin-scalar terms are more important than the $U$-spin vectors for various levels of demanded theoretical accuracy.