Speaker: Antoine GĂ©rardin (University of Mainz)
Title: The hadronic light-by-light scattering contribution to the muon g-2 from lattice QCD
Abstract: The anomalous magnetic moment of the muon is one of the most promising observables to identify hints for physics beyond the Standard Model of particle physics. This quantity exhibits a persistent discrepancy of 3.5 standard deviations between the direct measurement by the Brookhaven E821 Collaboration and its theoretical prediction based on the Standard Model. The theory error is now completely dominated by effects of the strong interaction and in particular by the hadronic light-by-light scattering (HLbL) contribution.
In addition to the direct lattice calculation of the full HLbL contribution, lattice QCD can provide valuable inputs to the recently proposed dispersive framework where experimental data are often missing. After presenting the lattice calculation of the pion-pole contribution, expected to be dominant, I will show that information about higher energy resonances can be extracted from the study of the forward light-by-light scattering amplitudes computed on the lattice.