Chiral partner structure of heavy baryons from the bound state approach with hidden local symmetry

Abstract

The chiral partner structure of heavy baryons is studied using the bound state approach by binding the heavy-light mesons to nucleon as soliton in an effective Lagrangian for the pseudoscalar and vector mesons based on the hidden local symmetry. In the heavy-light meson sector, we regard the $H$-doublet and $G$-doublet as chiral partners and couple them to light meson with minimal derivative. We find that the chiral partner of $\Lambda_c(1/2^+,2286)$ is the $\Lambda_c(1/2^-,3/2^-)$ heavy quark doublet with the mass of about 3.1\,GeV but not ($\Lambda_c(1/2^-,2595)$, $\Lambda_c(3/2^-,2625)$) which might be interpreted as an orbital excitation of the $\Lambda_c(1/2^+,2286)$. The same model is applied to the bottom sector, and the chiral partner of $\Lambda_b(1/2^+,5625)$ is shown to have the mass of about 6.5\,GeV. The chiral partner structures for the isospin vector heavy baryons are also discussed. For the pentaquark states, we find that the masses of the pentaquark state made of ground state heavy-light meson and its chiral partner are similar, and both of them are below the $Dp$ threshold, which therefore cannot be ruled out by the present data.