Measurement of the Electromagnetic Transition Form-factors in the decays ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{l}^{+}{l}^{-}$

BESIII Collaboration, M. Ablikim, M. N. Achasov +628

With a sample of $(10087\pm 44)\times 10^6$ $J/\psi$ events accumulated with the BESIII detector, we analyze the decays ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{l}^{+}{l}^{-}(l=e,$ $\mu )$ via the process $J/ψ\righ…