Analysis of $Λ_c(2595)$, $Λ_c(2625)$, $Λ_b(5912)$, $Λ_b(5920)$ based on a chiral partner structure

Abstract

We construct an effective hadronic model including $Λ_c(2595)$, $Λ_c(2625)$, $Λ_b(5912)$ and $Λ_b(5920)$ regarding them as chiral partners to $Σ_c(2455)$, $Σ_c(2520)$, $Σ_b$ and $Σ_b^\ast$, 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 $Σ_c^{(\ast)}$ and $Λ_c(2595)$. Then, we study the decay widths of $Λ_c(2625)$, $Λ_b(5912)$ and $Λ_b(5920)$. We find that, although the decay of $Λ_c(2595)$ is dominated by the resonant contribution through $Σ_c(2455)$, non-resonant contributions are important for $Λ_c(2625)$, $Λ_b(5912)$ and $Λ_b(5920)$, 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.

2 figures, 11 pages