Determination of Spin-Parity Quantum Numbers of X(2370) as 0−+ from

Based on (10087±44)×106 J/ψ events collected with the BESIII detector, a partial wave analysis of the decay J/ψ→γKS0KS0η′ is performed. The mass and width of the X(2370) are measured to be 2395±11(stat)−94+26(syst) MeV/c2 and 188−17+18(stat)−33+124(syst) MeV, respectively. The corresponding product branching fraction is B[J/ψ→γX(2370)]×B[X(2370)→f0(980)η′]×B[f0(980)→KS0KS0]=(1.31±0.22(stat)−0.84+2.85(syst))×10−5. The statistical significance of the X(2370) is greater than 11.7σ and the spin parity is determined to be 0−+ for the first time. The measured mass and spin parity of the X(2370) are consistent with the predictions of the lightest pseudoscalar glueball. Published by the American Physical Society 2024