On some implications of the BaBar data on the ${\gamma }^{\ast }{\eta }^{\prime }$ transition form factor

Peter Kroll, Kornelija Passek-Kumerički

At leading-twist accuracy the form factors for the transitions from a virtual photon to the $\eta$ or ${\eta }^{\prime }$ can be expanded into a power series of the variable $\omega$, being related to th…