Masses and decay widths of ${\Xi }_{c/b}$ and ${\Xi }_{c/b}^{\prime }$ baryons

Abstract

In this article, we present a complete classification of the negative parity ${\Xi }_{c/b}^{\prime }$ and ${\Xi }_{c/b}$ $P$-wave states: 7 belonging to the $SU(3)$ flavor sextet and 7 to the flavor anti-triplet, the calculation of the ${\Xi }_{c/b}^{\prime }$ and ${\Xi }_{c/b}$ strong partial decay widths into ${}^2{\Sigma }_c\bar{K}$, ${}^2{\Xi }_c^{{}^{\prime }}\pi$, ${}^2{\Sigma }_c\bar{K}$, ${}^4{\Xi }_c^{{}^{\prime }}\pi$, ${\Lambda }_c^{{}^{\prime }}\bar{K}$, ${\Xi }_c^{}\pi$ and ${\Xi }_c^{}\eta$ channels both within the Elementary Emission Model (EEM) and the ${}^3{P}_0$ model, and the calculation of the electromagnetic decay widths for ${\Xi }_{c/b}^{\prime }$ and ${\Xi }_{c/b}$ radiative decays. By means of the equal-spacing mass rule and by the analysis of the strong partial decay widths, we suggest possible assignments for the new LHCb ${\Xi }_c(2923)$, ${\Xi }_c(2939)$, and ${\Xi }_c(2965)$ states, as well as for the ${\Xi }_c$'s previously reported by Belle and BaBar. Our results can be tested by future experiments, at LHCb and Belle, disentangling the remaining missing piece of information, {\it i.e.} the quantum numbers. Finally, a comparison is made between a three-quark and a quark-diquark description of ${\Xi }_c$ states. Very recently the LHCb collaboration reported the observation of two new ${\Xi }_b$ states, namely ${\Xi }_b(6327{)}^0$ and ${\Xi }_b(6333)$, in ${\Lambda }_b^0{K}^{-}{\pi }^{+}$ channel with a statistical significance larger than nine standard deviations. The experimental masses and widths of these two states are consistent with our mass and width predictions for the doublet of D-wave excitations of the ${\Xi }_b$ system with $J_{{\Xi }_b(6327{)}^0}^P={\frac{3}{2}}^{+}$ and $J_{{\Xi }_b(6333{)}^0}^P={\frac{5}{2}}^{+}$.

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