Interpretation of $\Omega (2012)$ as a $\Xi (1530)K$ molecular state

Abstract

We investigate the mass and strong decay properties of the $\Omega (2012)$ resonance using QCD sum rules, assuming it to be an S-wave $\Xi (1530)\bar{K}$ molecular pentaquark state with $I(J^P)=0({\frac{3}{2}}^{-})$. A unified interpolating current is constructed, and the two-point correlation functions and three-point functions are calculated up to dimension-13 and 10 condensate terms in the OPE series, respectively. The negative-parity contribution is isolated by employing parity-projected sum rules. The two-body strong decays to ${\Xi }^0{K}^{-}$ and ${\Xi }^{-}{\bar{K}}^0$ are studied via their three-point correlation functions. Our analysis yields a mass of $2.00\pm 0.15\mathrm{GeV}$ and a total two-body decay width of $\Gamma =0.96_{-0.41}^{+0.79}\mathrm{MeV}$ for the $\Xi (1530)\bar{K}$ molecular state. The ratio of the two-body decay branching fractions is obtained as ${\mathcal{R}}_{{\Xi }^0{K}^{-}}^{{\Xi }^{-}{\bar{K}}^0}=0.85$. These results are compatible with the experimental data for the $\Omega (2012)$ within uncertainties and support its interpretation as a $\Xi (1530)\bar{K}$ molecular pentaquark state.

Comments: 13 pages, 10 figures. Accepted by Chinese Physics C