P-wave charmed baryons from QCD sum rules
We study the P-wave charmed baryons using the method of QCD sum rule in the framework of heavy quark effective theory. We consider systematically all possible baryon currents with a derivative for internal ρ- and λ-mode excitations. We have found a good working window for the currents corresponding to the ρ-mode excitations for Λc(2595), Λc(2625), Ξc(2790), and Ξc(2815) that complete two SU(3) 3¯F multiplets of JP=1/2- and 3/2-, while the currents corresponding to the λ-mode excitations seem also consistent with the data. Our results also suggest that there are two Σc(2800) states of JP=1/2- and 3/2- whose mass splitting is 14±7  MeV, and two Ξc(2980) states whose mass splitting is 12±7  MeV. They have two Ωc partners of JP=1/2- and 3/2-, whose masses are around 3.25±0.20  GeV with mass splitting 10±6  MeV. All of them together complete two SU(3) 6F multiplets of JP=1/2- and 3/2-. They may also have JP=5/2- partners. Ξc(3080) may be one of them, and the other two are Σc(5/2-) and Ωc(5/2-), whose masses are 85±23  MeV and 50±27  MeV larger.