Study of the hidden-heavy pentaquarks and $P_{cs}$ states

In light of the recently observed resonance states $P_{\psi s}^{\mathrm{\Lambda }}(4338{)}^0$ and $P_{cs}(4459{)}^0$ by LHCb Collaboration in $J\mathrm{/}\psi \mathrm{\Lambda }$ decay channel, we perform a systematical study of all possible hidden-heavy pentaquarks with strangeness $S=0,-1,-2,-3$, in unified framework of MIT bag model. The color-spin wavefunctions presented in terms of Young-Yamanouchi bases and transformed into baryon-meson couplings, are utilized to calculate masses, magnetic moments and ratios of partial widths. With numerical analysis, the observed $P_{\psi s}^{\mathrm{\Lambda }}(4338{)}^0$ is likely to be a $1\mathrm{/}{2}^{-}$ compact $P_{cs}$ pentaquark, and $P_{cs}(4459{)}^0$ favors two-peak structure of $3\mathrm{/}{2}^{-}$ and $1\mathrm{/}{2}^{-}$ $P_{cs}$ states. Further predictions on hadron properties and decay channels are given to compact $P_{css}$, $P_{csss}$ states and bottom sectors.