Pseudoscalar transition form factors from rational approximants

Pseudoscalar Transition Form Factors are analyzed in the space-like region at the low- and intermediate- energy regions with rational approximants in a model-independent way. Low-energy parameters are, then, extracted from a fit to such data. The feasibility of the form factors to determine the η and η' mixing is analyzed as well as their implications into the light-by-light contribution to the anomalous magnetic moment and the pseudoscalar decays into a lepton pair.