N*(1520) transition form factors from dispersion theory

Abstract

The electromagnetic transition form factors (TFFs) of the nucleon provide important information on the internal structure of hadrons. A model-independent dispersive calculation of the electro magnetic TFFs N*(1520) → N at low energies is presented. Taking pion rescattering into consideration, we derived dispersive relations for the N*(1520) → N TFFs that relate space-like and time-like regions from the first principles. Based on the space-like data from JLab and hadronic data measured by HADES, we make predictions for TFFs in the time-like region. Our predictions can be tested in future experi ments (e.g. HADES).