Interpretation of recently discovered single bottom baryons in the relativistic flux tube model

Abstract

Following recent experimental progress in the study of bottom baryons, we systematically calculate the mass spectra of $Λ_{b}$, $Ξ_{b}$, $Σ_{b}$, $Ξ_{b}^{'}$, and $Ω_{b}$ baryons with a quark-diquark picture in the framework of a relativistic flux tube model with spin-dependent interactions in the j-j coupling scheme. Furthermore, we calculate the strong decay width of bottom baryons decaying into a bottom baryon and a light pseudoscalar meson. A good agreement is found between the calculated masses and the experimentally available masses of singly bottom baryons. %We interpret $Σ_{b}(6097)$ as a $1P(3/2^{-})$ state, $Ξ_{b}(6100)$ as $1P(1/2^{-})$ state of $Ξ_{b}$ baryon, $Ξ_{b}(6227)$ as a $1P(1/2^{-})$ or $1P(3/2^{-})$ state of $Ξ_{b}'$ baryon, $Ξ_{b}(6327)$ as a $1P(3/2^{-})$ state of $Ξ_{b}'$ baryon, and $Ξ_{b}(6333)$ as a $1P(3/2^{-})$ state of $Ξ_{b}'$ baryon. By analysing both mass spectra and strong decay widths, we interpret $Σ_{b}(6097)$ as a $1P(3/2^{-})$ state and $Ξ_{b}(6100)$ as a $1P(1/2^{-})$ state of $Ξ_{b}$ baryon. The $Ξ_{b}(6227)$ is identified to be an orbital excitation $1P$ of the $Ξ_{b}^{'}$ baryon with $J^{P}=3/2^{-}$. Further, we determine $Ξ_{b}(6327)$ and $Ξ_{b}(6333)$ as a $1P(3/2^{-})$ state and $1P(5/2^{-})$ state, respectively, of $Ξ_{b}^{'}$ baryon. From the obtained mass spectra, we construct the Regge trajectories in the $(J,M^{2})$ plane, which are found to be essentially linear, parallel, and equidistant. Our predictions for higher orbital and radial excited states can help experimentalists identify missing excited states of singly bottom baryons.