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

Abstract

Radiative decays of the $J/\ddot{I}ˆ$ particle are of gluon-rich environment, providing an ideal place for hunting glueballs. The $X(2370)$ particle was first discovered in $J/\ddot{I}ˆ\to {\hat{I}}^3\ddot{I}{€}^{+}\ddot{I}{€}^{-}\hat{I}{\cdot }^{\prime }$ process in 2011 with the BESIII experiment at BEPCII Collider, and later it was confirmed in $J/\ddot{I}ˆ\to {\hat{I}}^{3}K\bar{K}\hat{I}{\cdot }^{\prime }$ decays. In 2024, with a sample of 10 billion $J/\ddot{I}ˆ$ 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 $J/\ddot{I}ˆ\to {\hat{I}}^3{K}_S^0{K}_S^0\hat{I}{\cdot }^{\prime }$ process. Recently, new decay modes of $X(2370)\to K_S^0{K}_S^0\ddot{I}{€}^0$, $\ddot{I}{€}^0\ddot{I}{€}^0\hat{I}\cdot$ and $a^0\ddot{I}{€}^0$ 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.

21 pages, 17 figures, Invited review paper submitted to International Journal of Modern Physics A