Measurement of the ${\gamma }^{\star }{\gamma }^{\star }\to {\eta }^{\prime }$ transition form factor

The BaBar collaboration

We study the process $e^{+}{e}^{-}\to e^{+}{e}^{-}{\eta }^{\prime }$ in the double-tag mode and measure for the first time the ${\gamma }^{\star }{\gamma }^{\star }\to {\eta }^{\prime }$ transition form factor $F_{{\eta }^{\prime }}(Q_1^2,Q_2^2)$ in th…