Interpreting the Newly Observed $\mathrm{\Xi }(1720)$ State in the Spin-$\frac{3}{2}$ $\mathrm{\Xi }$ Spectrum

We analyze the low lying spin-$\frac{3}{2}$ $\mathrm{\Xi }$ spectrum by means of the two point QCD sum rule approach. The analysis is motivated by the BESIII observation of the $\mathrm{\Xi }(1720)$ resonance, reported with mass $1721.0\pm {5.2}_{\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}\mathrm{.}}\pm {3.4}_{\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t}\mathrm{.}}\mathrm{M}\mathrm{e}\mathrm{V}$ and favored quantum numbers $J^P={\frac{3}{2}}^{+}$. In this framework, we include the $1S$, $1P$, $2S$ and $2P$ configurations as possible low lying spin-$\frac{3}{2}$ cascade states. The extracted masses are $1527.53\pm 111.38\mathrm{M}\mathrm{e}\mathrm{V}$, $1615.30\pm 50.98\mathrm{M}\mathrm{e}\mathrm{V}$, $1727.52\pm 42.39\mathrm{M}\mathrm{e}\mathrm{V}$ and $1803.71\pm 64.50\mathrm{M}\mathrm{e}\mathrm{V}$ for the $1S$, $1P$, $2S$ and $2P$ states, respectively. The mass obtained for the $2S$ configuration agrees with the BESIII value within uncertainties and favors the assignment of $\mathrm{\Xi }(1720)$ as the first radial spin-$\frac{3}{2}$ excitation of the $\mathrm{\Xi }$ baryon.