Octet and decuplet baryon magnetic moments in the chiral quark model

Octet and decuplet baryon magnetic moments have been formulated within the chiral quark model (χ QM) with configuration mixing incorporating the sea quark polarizations and their orbital angular momentum through a generalization of the Cheng-Li mechanism. When the parameters of the χ QM without configuration mixing are fixed by incorporating the latest data pertaining to u-bar-d-bar asymmetry (E866) and the spin polarization functions, in the case of octet magnetic moments the results not only show improvement over the nonrelativistic quark model results but also give a nonzero value for the right hand side of the Coleman-Glashow sum rule, usually zero in most of the models. In the case of decuplet magnetic moments, we obtain a good overlap for Δ++, Ω-, and the transition magnetic moment ΔN for which data are available. In the case of the octet, the predictions of the χ QM with the generalized Cheng-Li mechanism show remarkable improvements in general when the effects of configuration mixing and 'mass adjustments' due to confinement are included, specifically in the case of p, Σ+, Ξ0, and the ΣΛ transition magnetic moment and in the violation of the Coleman-Glashow sum rule an almost perfect agreement with data is obtained. When the above analysis is repeated with the earlier NMC data, a similar level of agreement is obtained; however, the results in the case of E866 look to be better. In this case, we incorporate in our analysis the gluon polarization Δg, found phenomenologically through the relation ΔΣ(Q2)=ΔΣ-[3αs(Q2)/2π]Δg(Q2); not only do we obtain an improvement in the quark spin distribution functions and magnetic moments, but also the value of Δg comes out in good agreement with certain recent measurements as well as theoretical estimates