The X (2370) particle was first discovered in J → γ π + π − η ′ process in 2011 with the BESIII experiment at BEPCII Collider. In 2024, the spin-parity quantum numbers of the X (2370) was determined to be 0 − + in J → γ K S 0 K S 0 η ′ process. New decay modes of X ( 2370 ) → K S 0 K S 0 π 0 , π 0 π 0 η and a 0 π 0 were observed recently. 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.
Shan Jin (Fri,) studied this question.