Transition form factors ${\gamma }^{\ast }\gamma \to \eta$ and ${\gamma }^{\ast }\gamma \to {\eta }^{\prime }$ in QCD

S. S. Agaev, V. M. Braun, N. Offen +2

We update the theoretical framework for the QCD calculation of transition form factors ${\gamma }^{\ast }\gamma \to \eta$ and ${\gamma }^{\ast }\gamma \to {\eta }^{\prime }$ at large photon virtualities including full next-to-leading order…