Analysis of Λc (2595), Λc (2625), Λb (5912), Λb (5920) based on a chiral partner structure

Abstract

We construct an effective hadronic model including Λc(2595), Λc(2625), Λb(5912), and Λb(5920), regarding them as chiral partners to Σc(2455), Σc(2520), Σb, and Σb∗, respectively, with respecting the chiral symmetry and heavy-quark spin-flavor symmetry. We determine the model parameters from the experimental data for relevant masses and decay widths of Σc(∗) and Λc(2595). Then, we study the decay widths of Λc(2625), Λb(5912), and Λb(5920). We find that, although the decay of Λc(2595) is dominated by the resonant contribution through Σc(2455), nonresonant contributions are important for Λc(2625), Λb(5912), and Λb(5920), which reflects the chiral partner structure. We also study the radiative decays of the baryons, and show that each of their widths is determined from the radiative decay width of their chiral partners.