Hadronic light-by-light scattering in the anomalous magnetic moment of the muon

Hadronic light-by-light scattering in the anomalous magnetic moment of the muon ais one of two hadronic effects limiting the precision of the Standard Model predictionfor this precision observable, and hence the new-physics discovery potential of directexperimental determinations of a. In this contribution, I report on recent progress inthe calculation of this effect achieved both via dispersive and lattice QCD methods