Investigation of the strange pentaquark candidate $P_{\psi s}^{\Lambda }(4338){}^0$ recently observed by LHCb

Abstract

The recently observed strange pentaquark candidate, $P_{\psi s}^{\Lambda }(4338){}^0$, is investigated to provide information about its nature and substructure. To this end, its mass and width through the decay channels $P_{\psi s}^{\Lambda }(4338){}^0\to J/\psi \Lambda$ and $P_{\psi s}^{\Lambda }(4338){}^0\to {\eta }_c\Lambda$ are calculated by applying two- and three-point QCD sum rules, respectively. The state is considered as a ${\Xi }_c\bar{D}$ meson-baryon molecular structure with spin-parity quantum numbers $J^P={\frac{1}{2}}^{-}$. The obtained mass, $m_{P_{\psi s}^{\Lambda }(4338){}^0}=4338\pm 130\mathrm{MeV}$, and width, ${\Gamma }_{P_{\psi s}^{\Lambda }(4338){}^0}=10.40\pm 1.93\mathrm{MeV}$, are consistent with the experimental data within the presented uncertainties. This allows us to assign a ${\Xi }_c\bar{D}$ molecular structure of $J^P={\frac{1}{2}}^{-}$ for the $P_{\psi s}^{\Lambda }(4338){}^0$ state.

Comments: 14 Pages, 2 Figures and 2 Tables