Amplitude Analysis of the Isospin-Violating Decay $J/\psi \to \gamma \eta {\pi }^0$

BESIII Collaboration, M. Ablikim, M. N. Achasov +759

Using $(10087\pm 44)\times 10^6$ $J/\psi$ events collected with the BESIII detector, we perform the first amplitude analysis of the process $J/\psi \to \gamma \eta {\pi }^0$. The decay is dominated b…