Evidence for Two Excited $\Omega^{-}$ Hyperons

Abstract

Using $e^+e^-$ collision data corresponding to an integrated luminosity of 19,fb$^{-1}$ collected by the BESIII detector at center-of-mass energies ranging from 4.13 to 4.70,GeV, we report the first evidence for a new excited $\Omega^{-}$ hyperon, the $\Omega(2109)^{-}$, through the process $e^+ e^- \to \Omega(2109)^{-} \bar{\Omega}^{+} +c.c.$ with a significance of 4.1 $\sigma$. The mass and width of $\Omega(2109)^{-}$ are measured to be $2108.5 \pm 5.2_{\rm stat} \pm 0.9_{\rm syst}\,{\rm MeV}/c^{2}$ and $18.3 \pm 16.4_{\rm stat} \pm 5.7_{\rm syst}\,{\rm MeV}$, respectively. We also present evidence for a new production mechanism for the previously identified $\Omega(2012)^-$ via the process $e^+ e^- \to \Omega(2012)^{-} \bar{\Omega}^{+} +c.c.$ with a significance of 3.5 $\sigma$.