Determination of spin-parity quantum numbers of X(2370) as $0^{-+}$ from $J/\ddot{I}ˆ\to {\hat{I}}^3{K}_S^0{K}_S^0\hat{I}{\cdot }^{\prime }$

Abstract

Based on $(10087\pm 44)\times 10^6$ $J/\ddot{I}ˆ$ events collected with the BESIII detector, a partial wave analysis of the decay $J/\ddot{I}ˆ\to {\hat{I}}^3{K}_S^0{K}_S^0\hat{I}{\cdot }^{\prime }$ is performed. The mass and width of the $X(2370)$ are measured to be $2395\pm 11(\mathrm{stat}{)}_{-94}^{+26}(\mathrm{syst})\mathrm{MeV}/c^2$ and $188_{-17}^{+18}(\mathrm{stat}{)}_{-33}^{+124}(\mathrm{syst})\mathrm{MeV}$, respectively. The corresponding product branching fraction is $\mathcal{B}[J/\ddot{I}ˆ\to {\hat{I}}^{3}X(2370)]\times \mathcal{B}[X(2370)\to f_0(980)\hat{I}{\cdot }^{\prime }]\times \mathcal{B}[f_0(980)\to K_S^0{K}_S^0]=\left(1.31\pm 0.22(\mathrm{stat}{)}_{-0.84}^{+2.85}(\mathrm{syst})\right)\times 10^{-5}$. The statistical significance of the $X(2370)$ is greater than $11.7\ddot{I}ƒ$ 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.

8 pages, 2 figures