$P_{c\bar{c}s}(4459{)}^0$, $P_{c\bar{c}s}(4338{)}^0$ and mass spectrum of strange hidden-charm pentaquarks

Abstract

Strange hidden-charm pentaquark states have been systematically investigated within a diquark-triquark model. Through a Gaussian expansion method, masses of some diquarks, triquarks and strange hidden-charmed pentaquark states from S-wave to P-wave excitations have been calculated with the non-relativistic Semay and Silvestre-Brac potentials in terms of the same parameters employed for tetraquark states. Masses of pentaquark states in S-wave excitations are found between $4200$ MeV and $4590$ MeV, while masses of all P-wave excitations are found above $4600$ MeV. Mass splittings between the S-wave and P-wave pentaquark states are about $350-570$ MeV. In comparison to the experimental data, $P_{c\bar{c}s}(4459{)}^0$ observed by LHCb in decay channel ${\Xi }_b^{-}\to J/\psi \Lambda K^{-}$ is assumed as the $|1;0,1/2;3/2,0{⟩}_{3/2}$ $[sq][\bar{c}cq]$ pentaquark state with $J^P={\frac{3}{2}}^{-}$, while $P_{c\bar{c}s}(4338{)}^0$ observed in the decay channel $B^{-}\to J/\psi \Lambda \bar{p}$ is very possibly the $|0;1,1/2;1/2,0{⟩}_{1/2}$ $[cq][\bar{c}sq]$ pentaquark state with $J^P={\frac{1}{2}}^{-}$. We predict a lowest strange hidden-charm pentaquark state with $J^P={\frac{1}{2}}^{-}$ around $4200$ MeV.

20 pages, 7 tables