QCD sum rule study for hidden-strange pentaquarks

Abstract

Inspired by the LHCb's observations of hidden-charm $P_{c(s)}$ states, we study their hidden-strange analogues $P_s$ states in both $[udu][\bar{s}s]$ and $[uds][\bar{s}u]$ configurations. We investigate the $P_s$ pentaquark states in $p{\eta }^{\prime }$, $p\varphi$, $\Lambda K$, $\Sigma K$ 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 $p{\eta }^{\prime }$, $p\varphi$, $\Lambda K$, $\Sigma K$ 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.

Comments: 13 pages, 4 figures. To be published in Chinese Physics C