Study of the electromagnetic Dalitz decay $J/\ddot{I}ˆ\to e^{+}{e}^{-}\ddot{I}{€}^0$

BESIII Collaboration, M. Ablikim, M. N. Achasov +640

We report the first measurement of the di-electron invariant mass dependent transition form factor in the electromagnetic Dalitz decay $J/\ddot{I}ˆ\to e^{+}{e}^{-}\ddot{I}{€}^0$ using $(10087 \pm 44) \…