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Determination of Spin-Parity Quantum Numbers of $X\left(2370\right)$ as ${0}^{-+}$ from $J/\psi \to \gamma {K}_{S}^{0}{K}_{S}^{0}{\eta }^{\prime }$

2024    CERN İşbirliği

Based on $\left(10087±44\right)×{10}^{6}\text{}\text{}J/\psi $ events collected with the BESIII detector, a partial wave analysis of the decay $J/\psi \to \gamma {K}_{S}^{0}{K}_{S}^{0}{\eta }^{\prime }$ is performed. The mass and width of the $X\left(2370\right)$ are measured to be $2395±11\left(\mathrm{stat}{\right)}_{-94}^{+26}\left(\mathrm{syst}\right)\text{}\text{}\mathrm{MeV}/{c}^{2}$ and ${188}_{-17}^{+18}\left(\mathrm{stat}{\right)}_{-33}^{+124}\left(\mathrm{syst}\right)\text{}\text{}\mathrm{MeV}$, respectively. The corresponding product branching fraction is $B\left[J/\psi \to \gamma X\left(2370\right)\right]×B\left[X\left(2370\right)\to {f}_{0}\left(980\right){\eta }^{\prime }\right]×B\left[{f}_{0}\left(980\right)\to {K}_{S}^{0}{K}_{S}^{0}\right]=\phantom{\rule{0ex}{0ex}}\left(1.31±0.22\left(\mathrm{stat}{\right)}_{-0.84}^{+2.85}\left(\mathrm{syst}\right)\right)×{10}^{-5}$. The statistical significance of the $X\left(2370\right)$ is greater than $11.7\sigma $ and the spin parity is determined to be ${0}^{-+}$ for the first time. The measured mass and spin parity of the $X\left(2370\right)$ are consistent with the predictions of the lightest pseudoscalar glueball.