Hadronic light-by-light scattering in the muon g-2

Understand

We briefly review the current status of the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon.

• Based on various model calculations in the literature, we obtain the estimate a_{mu}^{HLbL} = (102 \pm 39) x 10^{-11}.
• Recent developments including more model-independent approaches using dispersion relations and lattice QCD, that could lead to a more reliable estimate, are also discussed.