Analysis of the J/ψ → π0γ* transition form factor

In view of the first measurement of the branching fraction for J/Psi -> pi(0)e(+)e(-) by the BESIII collaboration, we analyze what can be learned on the corresponding transition form factor using dispersion theory. We show that light-quark degrees of freedom dominate the spectral function, in particular two-pion intermediate states. Estimating the effects of multipion states as well as charmonium, we arrive at a prediction for the complete form factor that should be scrutinized experimentally in the future.