Speaker
Gernot Eichmann
(University of Giessen)
Description
The light-by-light scattering contribution to the muon anomalous magnetic moment is discussed from the Dyson-Schwinger perspective. The structure of the four-photon amplitude and the various slices of the phase space that play an important role for the muon g-2 are examined. The systematic construction of the four-photon vertex from the quark level satisfies electromagnetic gauge invariance by construction; it contains quark loops but also all intermediate meson resonances in the two-photon channels. It depends on the quark-photon and quark-Compton vertices which also enter in the calculation of nucleon form factors and the nucleon Compton scattering amplitude. In this way it becomes possible to link together a variety of electromagnetic processes from the same underlying building blocks. I will present first results for the muon g-2 and discuss how they compare with present model calculations.
Author
Gernot Eichmann
(University of Giessen)
