Exploring the properties of low-lying excited $Ξ_c$ and $Ξ_c'$ baryons
Motivated by the rapidly accumulating experimental data, we systematically calculate the $Ξ_c$ and $Ξ_c'$ mass spectra for the $1S$-, $1P$-, and $1D$-wave states and investigate the strong decay properties of the $1P$- and $1D$-wave states, thereby interpreting the internal structure of the currently controversial excited states and providing useful guidance for future experimental searches. The main conclusions are summarized as follows. $Ξ_c(2790)$ and $Ξ_c(2815)$ can be well explained as $Ξ_c1P\big|J^P=1/2^-,1\big\rangle_λ$ and $Ξ_c1P\big|J^P=3/2^-,1\big\rangle_λ$, respectively. $Ξ_c(2882)$ may correspond to $Ξ_c1P\big|J^P=1/2^-,0\big\rangle_ρ$ or $Ξ_c1P\big|J^P=1/2^-,1\big\rangle_ρ$; under this interpretation, $Ξ_cπ$ and $Ξ_c'π$ would be promising channels for its detection. $Ξ_c(2923)$ might be assigned to $Ξ_c'1P\big|J^P=3/2^-,1\big\rangle_λ$, but further confirmation is required. $Ξ_c(2939)$ is very likely to be $Ξ_c'1P\big|J^P=3/2^-,2\big\rangle_λ$ and has a good potential to be observed in the final states $Ξ_cπ$ and $Ξ_c'^{*}π$. $Ξ_c(2965)$ can be explained as $Ξ_c'1P\big|J^P=5/2^-,2\big\rangle_λ$ and $Ξ_cπ$ decay channel is a promising additional mode for future experimental searches. $Ξ_c(3055)$ and $Ξ_c(3080)$ can be assigned as the quark configurations $Ξ_c1D\big|J^P=3/2^+,2\big\rangle_{λλ}$ and $Ξ_c1D\big|J^P=5/2^+,2\big\rangle_{λλ}$, respectively. $Ξ_c(3123)$ is possibly state $Ξ_c'1D\big|J^P=1/2^+,1\big\rangle_{λλ}$ or $Ξ_c'1D\big|J^P=5/2^+,3\big\rangle_{λλ}$, with the latter being more favorable. Decay channels $Λ/ΣD$ are very likely to serve as a criterion for distinguishing between these two possible candidates.