Research in our group is focused on hadronic physics at low energy, where strong interactions are fully non-perturbative. We study them with the effective-Lagrangian approach and combine this with the use of dispersion relations, which can significantly extend the range of applicability towards higher energies. In recent years we have focused on processes and observables involving photons. This started with the study of the hadronic light-by-light contribution to the muon g-2, for which our group was the first to formulate a dispersive treatment. More recently we have focused on radiative and strong isospin-breaking corrections to e+e- -> pi+pi- and tau -> pi pi0 nu. These studies not only have a strong phenomenological interest, but also offer a very interesting theoretical challenge. In processes involving photons and hadrons at the same time one has to treat one interaction (QED) perturbatively, whereas the other (the strong) non-perturbatively with dispersion relations and EFT. The difficulty of such a treatment is also related to the presence of infrared singularities due to photons. The focus is at the moment on hadronic contributions to the muon g-2 but we also plan to extend the applications to other processes.
