Hadronic molecular assignment for the newly observed ${\mathrm{\Omega }}^{*}$ state

Very recently, a new ${\mathrm{\Omega }}^{*}$ state was reported by the Belle Collaboration, with its mass of $2012.4\pm 0.7(\text{stat})\pm 0.6(\text{syst})\mathrm{MeV}$, which locates just below the $K{\mathrm{\Xi }}^{*}$ threshold and hence hints to be a possible $K{\mathrm{\Xi }}^{*}$ hadronic molecule. Using the effective Lagrangian approach as the same as our previous works for other possible hadronic molecular states, we investigate the decay behavior of this new ${\mathrm{\Omega }}^{*}$ state within the hadronic molecular picture. The results show that the measured decay width can be reproduced well and its dominant decay channel is predicted to be the $K\pi \mathrm{\Xi }$ three-body decay. This suggests that the newly observed ${\mathrm{\Omega }}^{*}$ may be ascribed as the $J^P={3/2}^{-}K{\mathrm{\Xi }}^{*}$ hadronic molecular state and can be further checked through its $K\pi \mathrm{\Xi }$ decay channel.

Figure 1

The three-body decays of $\mathrm{\Omega }(2012)$ in the $\mathrm{\Xi }(1530)K$ molecular picture.

Figure 2

The triangle diagram for the two-body decay of the $\mathrm{\Omega }(2012)$ in the $\mathrm{\Xi }(1530)K$ molecular picture.

Figure 3

Dependence of the total decay width and partial decay widths of $K\pi \mathrm{\Xi }$, $K\mathrm{\Xi }$, as well as the partial widths of $\rho$, $\omega$, $\varphi$ exchange in the two-body $K\mathrm{\Xi }$ decay channel on the cutoffs in the $S$-wave $K{\mathrm{\Xi }}^{*}$ molecular scenario for $\mathrm{\Omega }(2012)$: (left) ${\mathrm{\Lambda }}_0$ changes with ${\mathrm{\Lambda }}_1$ fixed at 1.2 GeV; (right) ${\mathrm{\Lambda }}_1$ changes with ${\mathrm{\Lambda }}_0$ fixed at 1.0 GeV.

Figure 4

Dependence of the branch ratio of $K\mathrm{\Xi }$ channel on the cutoff ${\mathrm{\Lambda }}_0$ (Red) and ${\mathrm{\Lambda }}_1$ (Blue).

Figure 5

Dependence of the total decay width and partial decay widths of $K\pi \mathrm{\Xi }$, $K\mathrm{\Xi }$, as well as the partial widths of $\rho$, $\omega$, $\varphi$ exchange in the two-body $K\mathrm{\Xi }$ decay channel on the reported mass of $\mathrm{\Omega }(2012)$.