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 $2108.5\pm 5.2_{\mathrm{stat}}\pm 0.9_{\mathrm{syst}}\mathrm{MeV}/c^2$ and $18.3\pm 16.4_{\mathrm{stat}}\pm 5.7_{\mathrm{syst}}\mathrm{MeV}$, 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 $\sigma$.

Comments: 8 pages, 2 figures