Charmonium in China: BEPCII/BESIII

Abstract

Results based on 106 M $\psi'$ events and about 226 M $J/\psi$ events acquired with the BESIII detector at BEPCII are reported, including a confirmation of the BESII $p\bar{p}$ threshold enhancement in $J/\psi \to \gamma p\bar{p}$, branching ratios for $\chi_{cJ} \to \pi^0 \pi^0$ and $\eta \eta$, and first measurements of the branching ratios for $\psi' \to \pi^0 h_c$ and $h_c \to \gamma \eta_c$, as well as measurements of the mass and width of the $h_c$. Also reported are first observations of the two photon process $\psi' \to \gamma \gamma J/\psi$ and $f_0(980) - a_0(980)$ mixing.