Reanalysis of the newly observed ${\Omega }^{\ast }$ state in hadronic molecule model

Abstract

After the discovery of the new ${\Omega }^{\ast }$ state, the ratio of the branching fractions of $\Omega (2012)\to \bar{K}\pi \Xi$ relative to $\bar{K}\Xi$ decay channel was investigated by the Belle Collaboration recently. The measured $11.9\%$ up limit on this ratio is in sharp tension with the $S$-wave $\bar{K}\Xi (1530)$ molecule interpretation for $\Omega (2012)$ which indicates the dominant $\bar{K}\pi \Xi$ three-body decay. In the present work, we try to explore the possibility of the $P$-wave molecule assignments for $\Omega (2012)$ (where $\Omega (2012)$ has positive parity). It is found that the latest experimental measurements are compatible with the $1/2^{+}$ and $3/2^{+}$ $\bar{K}\Xi (1530)$ molecular pictures, while the $5/2^{+}$ $\bar{K}\Xi (1530)$ molecule shows the larger $\bar{K}\pi \Xi$ three-body decay compared with the $\bar{K}\Xi$ decay as the case of $S$-wave molecule. Thus, the newly observed $\Omega (2012)$ can be interpreted as the $1/2^{+}$ or $3/2^{+}$ $\bar{K}\Xi (1530)$ molecule state according to current experiment data.

Comments: 8pages, 6figures