We briefly review several activities at Mainz related to hadronic light-by-light scattering (HLbL) using lattice QCD. First we present a position-space approach to the HLbL contribution in the muon g-2, where we focus on exploratory studies of the pion-pole contribution in a simple model and the lepton loop in QED in the continuum and in infinite volume. The second part describes a lattice calculation of the double-virtual pion transition form factor F_{pi^0 gamma^* gamma^*}(q_1^2, q_2^2) in the spacelike region with photon virtualities up to 1.5 GeV^2 which paves the way for a lattice calculation of the pion-pole contribution to HLbL. The third topic involves HLbL forward scattering amplitudes calculated in lattice QCD which can be described, using dispersion relations (HLbL sum rules), by gamma^* gamma^* -> hadrons fusion cross sections and then compared with phenomenological models.
@article{arxiv.1801.04238,
title = {Hadronic light-by-light scattering contribution to the muon g-2 on the lattice},
author = {Nils Asmussen and Antoine Gerardin and Jeremy Green and Oleksii Gryniuk and Georg von Hippel and Harvey B. Meyer and Andreas Nyffeler and Vladimir Pascalutsa and Hartmut Wittig},
journal= {arXiv preprint arXiv:1801.04238},
year = {2018}
}
Comments
8 pages, 19 figures, contribution to the proceedings of FCCP2017 - Workshop on "Flavour changing and conserving processes", 7-9 September 2017, Anacapri, Capri Island, Italy