Discovery of a Glueball-like particle X(2370) at BESIII

Abstract

Radiative decays of the $J/\psi$ particle are of gluon-rich environment, providing an ideal place for hunting glueballs. The $X(2370)$ particle was first discovered in $J/\psi\to \gamma \pi^+\pi^-\eta^{\prime}$ process in 2011 with the BESIII experiment at BEPCII Collider, and later it was confirmed in $J/\psi\to\gamma K\bar{K}\eta^{\prime}$ decays. In 2024, with a sample of 10 billion $J/\psi$ events collected at the BESIII detector, the spin-parity of the $X(2370)$ was determined to be $0^{-+}$ for the first time in the partial wave analysis of $J/\psi\to \gamma K^{0}_{S}K^{0}_{S} \eta^{\prime}$ process. Recently, new decay modes of $X(2370)\to K^{0}_{S}K^{0}_{S}\pi^0$, $\pi^0\pi^0\eta$ and $a^0\pi^0$ were observed. The mass, spin-parity quantum numbers, production and decay properties of the $X(2370)$ particle are consistent with the features of the lightest pseudoscalar glueball.