$a_0(980)$ production, triangle singularity, and non-$\varphi$ background in the $J/\psi \to \varphi \eta {\pi }^0$ reaction

Hai-Peng Li, Wei-Hong Liang, Chu-Wen Xiao +1

We study the $J/\psi \to \varphi \eta {\pi }^0$ reaction measured recently by the BESIII collaboration with high precision, paying attention to three important aspects: 1) The production of the $a_0(…