Implications of baryon magnetic moments for the quark model

The implications of recent baryon-magnetic-moment measurements for various assumptions in the quark model are considered. The static quark model is seen to give a qualitative understanding of the baryon magnetic moments, but fails in a quantitative test (chi2/DF = 21.5/5), largely due to inconsistency of the now accurate determinations of the Λ0 and Ψ0 moments. Introducing nonstatic effects (orbital, relativistic, or exchange) still permits four independent sum rules to be written (for eight moments) if approximate SU(3) symmetry is assumed for quark-model wave functions. Two sum rules give good agreement with experiment, but those sum rules for any case involving the Ψ- or Σ- moments do not, suggesting that their experimental determination is inconsistent with such a quark model