Determination of Spin-Parity Quantum Numbers of X (2370) as 0-+ from J/ψ →γ KS0 KS0 η′

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.