Dispersive approach to hadronic light-by-light scattering
arXiv:1402.7081 · doi:10.1007/JHEP09(2014)091
Abstract
Based on dispersion theory, we present a formalism for a model-independent evaluation of the hadronic light-by-light contribution to the anomalous magnetic moment of the muon. In particular, we comment on the definition of the pion pole in this framework and provide a master formula that relates the effect from pi pi intermediate states to the partial waves for the process gamma^* gamma^* --> pi pi. All contributions are expressed in terms of on-shell form factors and scattering amplitudes, and as such amenable to an experimental determination.
33 pages, 4 figures; version accepted for publication in JHEP, improved presentation, including non-diagonal kernels for the S-waves