Light-by-Light Contribution to the Anomalous Magnetic Moment of Muon within the Nonlocal Chiral Quark Models

A brief review of recent nonlocal quark model calculations of the hadronic light-by-light contribution to the muon’s anomalous magnetic moment is presented. To the leading order in $$1{\\kern 1pt} /{\\kern 1pt} {{N}_{{\\text{c}}}}$$ , the contribution consists of a quark box diagram supplemented by resonance exchanges. A key point in these calculations is that the two-photon transition form factors of the mesons in the model depend not only on the photons’ virtualities but also on that of the meson. Consequently, the quark box diagram provides the correct OPE asymptotic. It is shown that the model’s result is quite stable when the model is extended to include spin-1 particles.