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

Inspired by the recently observed resonance states $P_{\psi s}^{\Lambda }(4338{)}^0$ and $P_{cs}(4459{)}^0$ by LHCb Collaboration in $J/\psi \Lambda$ 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 wave functions in terms of Young-Yamanouchi bases and transformed into baryon-meson couplings are utilized to calculate masses, magnetic moments, and relative partial widths of the hidden-heavy pentaquarks, suggesting that the observed $P_{\psi s}^{\Lambda }(4338{)}^0$ is likely to be a $1/2^{-}$ compact $P_{cs}$ pentaquark, and the $P_{cs}(4459{)}^0$ favors two-peak structure of $3/2^{-}$ and $1/2^{-}$ $P_{cs}$ states. Our computation indicates that hidden-heavy pentaquarks have the masses around 4.35–4.90 GeV for the $P_{cs}$, 11.21–11.67 GeV for the $P_{bs}$, 4.73–5.02 GeV for the $P_{css}$, and 11.54–11.77 GeV for the $P_{bss}$.