Analysis of $\Lambda_c(2595)$, $\Lambda_c(2625)$, $\Lambda_b(5912)$, $\Lambda_b(5920)$ based on a chiral partner structure

TL;DR

This paper develops an effective hadronic model respecting chiral and heavy-quark symmetries to analyze the properties and decay behaviors of certain heavy baryons, highlighting the importance of non-resonant contributions and chiral partner relationships.

Contribution

The study introduces a chiral partner framework for heavy baryons and determines decay properties using experimental data, emphasizing non-resonant effects and symmetry considerations.

Findings

Non-resonant contributions are significant for certain baryon decays.

Decay widths of baryons are linked to their chiral partners' radiative decays.

The model successfully reproduces experimental mass and decay data.

Abstract

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