Masses and decay widths of $\Xi_{c/b}$ and $\Xi^\prime_{c/b}$ baryons

Abstract

In this article, we present a complete classification of the negative parity $\Xi'_{c/b}$ 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 $\Xi'_{c/b}$ and $\Xi_{c/b}$ strong partial decay widths into $^2\Sigma_c \bar{K}$, $^2\Xi_c^{'} \pi$, $^2\Sigma_c \bar{K}$, $^4\Xi_c^{'} \pi$, $\Lambda_c^{'} \bar{K}$, $\Xi_c^{} \pi$ and $\Xi_c^{} \eta$ channels both within the Elementary Emission Model (EEM) and the $^3P_0$ model, and the calculation of the electromagnetic decay widths for $\Xi'_{c/b}$ 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 $J^{P}_{\Xi_b(6327)^{0}}=\frac{3}{2}^{+}$ and $J^{P}_{\Xi_b(6333)^{0}}=\frac{5}{2}^{+}$.