Magnetic moments of the low lying and charmed spin ${\frac{1}{2}}^{+}$ and spin ${\frac{3}{2}}^{+}$ baryons have been calculated in the $SU(4)$ chiral constituent quark model ($\chi \mathrm{CQM}$) by including the contribution from $c\overline{c}$ fluctuations. Explicit calculations have been carried out for the contribution coming from the valence quarks, “quark sea” polarizations and their orbital angular momentum. The implications of such a model have also been studied for magnetic moments of the low lying spin ${\frac{3}{2}}^{+}\to {\frac{1}{2}}^{+}$ and ${\frac{1}{2}}^{+}\to {\frac{1}{2}}^{+}$ transitions as well as the transitions involving charmed baryons. The predictions of $\chi \mathrm{CQM}$ not only give a satisfactory fit for the baryons where experimental data is available but also show improvement over the other models. In particular, for the case of $\mu (p)$, $\mu ({\Sigma }^{+})$, $\mu ({\Xi }^0)$, $\mu (\Lambda )$, Coleman-Glashow sum rule for the low lying spin ${\frac{1}{2}}^{+}$ baryons and $\mu ({\Delta }^{+})$, $\mu ({\Omega }^{-})$ for the low lying spin ${\frac{3}{2}}^{+}$ baryons, we are able to achieve an excellent agreement with data. For the spin ${\frac{1}{2}}^{+}$ and spin ${\frac{3}{2}}^{+}$ charmed baryon magnetic moments, our results are consistent with the predictions of the QCD sum rules, light cone sum rules and spectral sum rules. For the cases where light quarks dominate in the valence structure, the sea and orbital contributions are found to be fairly significant however, they cancel in the right direction to give the correct magnitude of the total magnetic moment. On the other hand, when there is an excess of heavy quarks, the contribution of the quark sea is almost negligible, for example, $\mu ({\Omega }_c^0)$, $\mu ({\Lambda }_c^{+})$, $\mu ({\Xi }_c^{+})$, $\mu ({\Xi }_c^0)$, $\mu ({\Omega }_{cc}^{+})$, $\mu ({\Omega }^{-})$, $\mu ({\Omega }_c^{*0})$, $\mu ({\Omega }_{cc}^{*+})$, and $\mu ({\Omega }_{ccc}^{*++})$. The effects of configuration mixing and quark masses have also been investigated.

• Received 25 February 2010

DOI:https://doi.org/10.1103/PhysRevD.81.073001