Study of the mass spectra of doubly heavy ₐₐ^ and ₐₐ^ baryons

Abstract LHCb Collaboration first observed a doubly charmed baryon ^++₂₂ Ξ cc + + in the ^+₂K^- ^+ ^+ Λ c + K - π + π + decay with a mass of 3621. 40 0. 72 0. 27 3621. 40 ± 0. 72 ± 0. 27 MeV. In this paper, we enumerated the mass spectra of the radial and orbital excited states for the doubly heavy ₐₐ^ Ξ Q Q ′ and ₐₐ^ Ω Q Q ′ baryons using the Regge trajectory model and the scaling rules. Our studies suggest that ^++₂₂ Ξ cc + + can be grouped into the 1 S -wave state with the spin-parity quantum number J^P = 1/2^+ J P = 1 / 2 +. On the other hand, the mass of ₂₂ Ξ cc state with J^P = 3/2^+ J P = 3 / 2 + is predicted to be 3699. 69 4. 59 3699. 69 ± 4. 59 MeV. We also predict the mass spectra of the unknown ground and excited states for the doubly heavy ₐₐ^ Ξ Q Q ′ and ₐₐ^ Ω Q Q ′ baryons, which provide useful references for the experimental test in the future.