Decays of Roper-like singly heavy baryons in a chiral model

Abstract

We present a chiral model describing decays of the Roper-like ${\mathrm{\ensuremath{\Lambda}}}_{c}(2765)$ and ${\mathrm{\ensuremath{\Xi}}}_{c}(2970)$ as well as those of the heavy quark spin-doublet ${{\mathrm{\ensuremath{\Sigma}}}_{c}(2455),{\mathrm{\ensuremath{\Sigma}}}_{c}(2520)}$ and ${{\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}},{\mathrm{\ensuremath{\Xi}}}_{c}(2645)}$, by focusing on chiral representations of diquarks inside the heavy baryons. Based on our chiral model together with the heavy quark spin symmetry, we derive a relation satisfied by axial charges of the heavy baryons that controls the magnitude of their one pion (kaon) decays. Besides, it is shown that the large decay widths of the Roper-like ${\mathrm{\ensuremath{\Lambda}}}_{c}(2765)$ and ${\mathrm{\ensuremath{\Xi}}}_{c}(2970)$, which cannot be implemented by conventional nonrelativistic quark models, are explained by reasonable values of the axial charges. In addition, we apply the chiral model to bottom baryons and predict decay widths of the undiscovered Roper-like ${\mathrm{\ensuremath{\Xi}}}_{b}$. We expect that our present investigation leads to elucidation of dynamical properties of the excited heavy baryons from the viewpoint of chiral symmetry.