Short-Distance Constraints for the Hadronic Light-by-Light Contribution to the Muon g-2

In view of the upcoming results from the Fermilab E989 experiment, the 3 to 4 sigma discrepancy between the Standard Model prediction and the experimental value of the muon anomalous magnetic moment (muon g-2) is a very timely matter.  The theoretical uncertainty of the muon g-2 is currently dominated by hadronic contributions, of which the hadronic light-by-light (HLbL) contribution is notoriously difficult to calculate.  While the low-energy part of the HLbL contribution can be constrained from data in a dispersive approach, short-distance constraints (SDCs) on the HLbL tensor are important to constrain the mixed- and high-energy regions in a model-independent calculation.  In this talk, I will discuss SDCs for the HLbL contribution to the muon g-2, focusing mainly on longitudinal SDCs relevant for the dominant pseudoscalar-pole contribution (pion, eta and eta’).  I will present large-Nc Regge models which satisfy the asymptotic behaviour of the HLbL tensor, dictated by QCD, with an infinite tower of radially-excited pseudoscalar mesons [1910.13432, 1910.11881].  To conclude, I will also review other recent papers on the subject.