Recently, the LHCb Collaboration reported a new structure $P_{cs}(4459)$ with a mass of 19 MeV below the ${\mathrm{\Xi }}_c{\overline{D}}^{*}$ threshold. It may be a candidate of molecular state from the ${\mathrm{\Xi }}_c{\overline{D}}^{*}$ interaction. In the current work, we perform a coupled-channel study of the ${\mathrm{\Xi }}_c^{*}{\overline{D}}^{*}$, ${\mathrm{\Xi }}_c^{\prime }{\overline{D}}^{*}$, ${\mathrm{\Xi }}_c^{*}\overline{D}$, ${\mathrm{\Xi }}_c{\overline{D}}^{*}$, ${\mathrm{\Xi }}_c^{\prime }\overline{D}$, and ${\mathrm{\Xi }}_c\overline{D}$ interactions in the quasipotential Bethe-Salpeter equation approach. With the help of the heavy quark chiral effective Lagrangian, the potential is constructed by light meson exchanges. Two ${\mathrm{\Xi }}_c{\overline{D}}^{*}$ molecular states are produced with spin parities $J^P=1/2^{-}$ and $3/2^{-}$. The lower state with $3/2^{-}$ can be related to the observed $P_{cs}(4450)$ while two-peak structure cannot be excluded. Within the same model, other strange hidden-charm pentaquarks are also predicted. Two states with spin parities $1/2^{-}$ and a state with $3/2^{-}$ are predicted near the ${\mathrm{\Xi }}_c^{\prime }\overline{D}$, ${\mathrm{\Xi }}_c\overline{D}$, and ${\mathrm{\Xi }}_c^{*}\overline{D}$ thresholds, respectively. As two states near ${\mathrm{\Xi }}_c{\overline{D}}^{*}$ threshold, two states are produced with $1/2^{-}$ and $3/2^{-}$ near the ${\mathrm{\Xi }}_c^{\prime }{\overline{D}}^{*}$ threshold. The couplings of the molecular states to the considered channels are also discussed. The experimental research of those states are helpful to understand the origin and internal structure of the $P_{cs}$ and $P_c$ states.

• Received 1 February 2021
• Accepted 15 March 2021

DOI:https://doi.org/10.1103/PhysRevD.103.074007

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Published by the American Physical Society