Identifying the ${\Xi }_c^0$ baryons observed by LHCb as $P$-wave ${\Xi }_c^{\prime }$ baryons

Abstract

We systematically study mass spectra and decay properties of $P$-wave ${\Xi }_c^{\prime }$ baryons of the $SU(3)$ flavor $6_F$, 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 $56_{-35}^{+30}$ MeV larger than the ${\Xi }_c(2965{)}^0$, and its width is about $18.1_{-8.3}^{+19.7}$ MeV.

16 pages, 1 figure, 3 tables, accepted by PRD