Form factor ${\pi }^0\to {\gamma }^{\ast }+{\gamma }^{\ast }$ at different photon virtualities

A. Anselm, A. Johansen, E. Leader +1

The ${\pi }^0\gamma \gamma$ vertex for virtual photons of squared masses $q_1^2$ and $q_2^2$ plays a vital rôle in several physical processes; for example for $q_1^2<0$, $q_2^2<0$, in the two-pho…