$\eta$ and ${\eta }^{\mathrm{\prime }}$ transition form factors from Pad\'e approximants

We employ a systematic and model-independent method to extract, from space- and time-like data, the $\eta$ and ${\eta }^{\mathrm{\prime }}$ transition form factors (TFFs) obtaining the most precise determination for their low-energy parameters and discuss the ${\mathrm{\Gamma }}_{\eta \to \gamma \gamma }$ impact on them. Using TFF data alone, we also extract the $\eta -{\eta }^{\mathrm{\prime }}$ mixing parameters, which are compatible to those obtained from more sophisticated and input-demanding procedures.