Understanding the nature of $\Omega (2012)$ in a coupled-channel approach

Abstract

We perform a systematic analysis of the mass and strong decays of the $\Omega (2012)$ resonance in a coupled-channel approach of a bare three-quark state and a composite meson-baryon state. Besides the coupling of the bare state and ${\Xi }^{\ast }\bar{K}$ channel, the effective meson-baryon interactions are also included. We find a pole with mass of $2008$ MeV by solving the Bethe-Salpeter equation. The calculated decay widths and its ratios of branching fractions ${\mathcal{R}}_{\Xi \bar{K}}^{\Xi \pi \bar{K}}$ agree well with the new experimental measurement by Belle Collaboration. Our results suggest that both three-quark core and ${\Xi }^{\ast }\bar{K}$ channel are essential for the description of the $\Omega (2012)$ resonance. We expect that present calculations can help us to better understand the nature of $\Omega (2012)$ resonance.

Comments: 9 pages, 4 figures. Minor modifications, accepted version