We study the contribution to the proton's magnetic moment from a heavy quark sea in quantum chromodynamics. The heavy quark is integrated out perturbatively to obtain an effective dimension-6 magnetic moment operator composed of three gluon fields. The leading contribution to the matrix element in the proton comes from a quadratically divergent term associated with a light-quark tensor operator. With an approximate knowledge of the proton's tensor charge, we conclude that a heavy sea-quark contribution to the proton's magnetic moment is positive in the asymptotic limit. We comment on the implication of this result for the physical strange quark. © 2007 Elsevier B.V. All rights reserved.
Ji, X., & Toublan, D. (2007). Heavy-quark contribution to the proton’s magnetic moment. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 647(5–6), 361–365. https://doi.org/10.1016/j.physletb.2007.02.047