Identifying the $\Xi_c^0$ baryons observed by LHCb as $P$-wave $\Xi_c^\prime$ baryons

We systematically study mass spectra and decay properties of $P$-wave $\Xi_c^\prime$ baryons of the $SU(3)$ flavor $\mathbf{6}_F$, using the methods of QCD sum rules and light-cone sum rules within the framework of heavy quark effective theory. Our results suggest that the three excited $\Xi_c^0$ baryons recently observed by LHCb can be well explained as $P$-wave $\Xi_c^\prime$ baryons: the $\Xi_c(2923)^0$ and $\Xi_c(2939)^0$ are partner states of $J^P = 1/2^-$ and $3/2^-$ respectively, both of which contain one $\lambda$-mode orbital excitation; the $\Xi_c(2965)^0$ has $J^P = 3/2^-$, and also contains one $\lambda$-mode orbital excitation. We propose to search for another $P$-wave $\Xi_c^\prime$ state of $J^P = 5/2^-$ in the $\Lambda_c K/\Xi_c \pi$ mass spectral in future experiments. Its mass is about $56^{+30}_{-35}$ MeV larger than the $\Xi_c(2965)^0$, and its width is about $18.1^{+19.7}_{-~8.3}$ MeV.