QCD sum rule study for hidden-strange pentaquarks

Inspired by the LHCb's observations of hidden-charm $P_{c(s)}$ states, we study their hidden-strange analogues $P_s$ states in both $[udu][\bar ss]$ and $[uds][\bar su]$ configurations. We investigate the $P_s$ pentaquark states in $p\eta^\prime$, $p\phi$, $\Lambda K$, $\Sigma K$ and $\Sigma^\ast K^\ast$ structures with $J^P = \frac{1}{2}^-$ and $\Sigma ^\ast K$ and $\Sigma K^\ast$ with $J^P = \frac{3}{2}^-$, and calculate their masses in the framework of QCD sum rules. Our numerical results show that the extracted hadron masses for all the $p\eta^\prime$, $p\phi$, $\Lambda K$, $\Sigma K$ and $\Sigma^\ast K^\ast$ structures are much higher than $\Sigma K$ mass threshold and masses for $\Sigma ^\ast K$ and $\Sigma K^\ast$ also higher than threshold of corresponding hadron, so that no bound state exists in such channels, which is consistent with the experimental status to date.Comment: 13 pages, 4 figures. To be published in Chinese Physics