The muon g-2: Dyson-Schwinger status on hadronic light-by-light scattering

Understand

We give a status report on the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment from the Dyson-Schwinger approach.

• We discuss novel, model-independent properties of the light-by-light amplitude: we give its covariant decomposition in view of electromagnetic gauge invariance and Bose symmetry, and we identify the relevant kinematic regions that are probed under the integral.
• The decomposition of the amplitude at the quark level and the importance of its various diagrams are discussed and related to model approaches.