The hadronic light-by-light scattering contribution to the muon g-2

por Andreas Nyffeler (Harish-Chandra Research Institute)

jueves 4 jun. 2009 12:00 → 13:00 Europe/Madrid

Sala Seminarios IFIC (Edf. Institutos de Investigación)

We briefly review the various contributions to the anomalous magnetic moment of the muon in the Standard Model. We then focus on the hadronic light-by-light scattering contribution which is one major source of uncertainty in the theoretical prediction. It cannot be directly related to a measurable quantity and therefore one has to rely on hadronic models to calculate it. In order to reduce this model dependence, we present a new QCD short-distance constraint on the numerically dominant pion-exchange contribution. We then evaluate this contribution in the framework of large N_C QCD, using a pion-photon-photon form factor which fulfills all short-distance constraints. We also comment on the status of the other contributions in hadronic light-by-light scattering and give an outlook on how further improvements could be achieved. Finally, we present a new value for the muon g-2 in the Standard Model.

Diapositivas transpis746.pdf