The \begin{document}${{ ss \bar s \bar s}} $\end{document} tetraquark states and the structure of X (2239) observed by the BESIII collaboration

We investigate the mass spectrum of the \begin{document}$ ss \bar s \bar s $\end{document} tetraquark states in the relativized quark model. By solving the Schrodinger-like equation with the relativized potential, the masses of S- and P-wave \begin{document}$ ss \bar s \bar s $\end{document} tetraquarks are obtained. The screening effects are also taken into account. It is found that the resonant structure \begin{document}$ X(2239) $\end{document} observed in the \begin{document}$ e^+e^- \to K^+K^- $\end{document} process by the BESIII collaboration can be assigned as a P-wave \begin{document}$ 1^{--} $\end{document} \begin{document}$ ss \bar s \bar s $\end{document} tetraquark state. Furthermore, the radiative transition and the strong decay behavior of this structure are also estimated, which can provide helpful information for future experimental searches.