Mass Spectra of $\Lambda_Q\bar{\Sigma}_Q$ Hexaquark States in QCD Sum Rules

Abstract

Recently, the BESIII Collaboration indicate that no $\Lambda_c\bar{\Sigma}_c$ bound-state with a mass near threshold in the range $4715$--$4735~\mathrm{MeV}$ was observed. In order to determine the plausible mass region of the states in this structure, we calculate the mass spectrum of the $\Lambda_c\bar{\Sigma}_c$ configuration with the method of QCD sum rules. Two linearly independent interpolating currents are constructed, and contributions from nonperturbative condensates up to dimension 12 are included in the numerical results. Consequently, we obtain the masses of the candidate states with quantum numbers $J^P = 0^-,\,0^+,\,1^-,\,1^+$. Our results show that the central values of the $\Lambda_c\bar{\Sigma}_c$ ground-state masses lie around the $5.8~\mathrm{GeV}$ region, which do not support them as bound states and consistent with the findings reported by the BESIII Collaboration. Furthermore, we compute the mass spectrum of the $\Lambda_b\bar{\Sigma}_b$ states with quantum numbers $J^P = 0^-,\,0^+,\,1^-,\,1^+$, which could be served as hidden-bottom candidates in the experimental detecting.