Evidence for the decay $Ω_{c}^{0} \to π^+Ω(2012)^- \to π^+ (\bar{K}Ξ)^{-}$

Abstract

Using a data sample of 980~fb$^{-1}$ collected with the Belle detector operating at the KEKB asymmetric-energy $e^+e^-$ collider, we present evidence for the $Ω(2012)^-$ in the resonant substructure of $Ω_{c}^{0} \to π^+ (\bar{K}Ξ)^{-}$ ($(\bar{K}Ξ)^{-}$ = $K^-Ξ^0$ + $\bar{K}^0 Ξ^-$) decays. The significance of the $Ω(2012)^-$ signal is 4.2$σ$ after considering the systematic uncertainties. The ratio of the branching fraction of $Ω_{c}^{0} \to π^{+} Ω(2012)^- \to π^+ (\bar{K}Ξ)^{-}$ relative to that of $Ω_{c}^{0} \to π^{+} Ω^-$ is calculated to be 0.220 $\pm$ 0.059(stat.) $\pm$ 0.035(syst.). The individual ratios of the branching fractions of the two isospin modes are also determined, and found to be ${\cal B}(Ω_{c}^0 \to π^+ Ω(2012)^-) \times {\cal B}(Ω(2012)^- \to K^-Ξ^0)/{\cal B}(Ω_{c}^0 \to π^+ K^- Ξ^0)$ = (9.6 $\pm$ 3.2(stat.) $\pm$ 1.8(syst.))\% and ${\cal B}(Ω_{c}^0 \to π^+ Ω(2012)^-) \times {\cal B}(Ω(2012)^- \to \bar{K}^0 Ξ^-)/{\cal B}(Ω_{c}^0 \to π^+ \bar{K}^0 Ξ^-)$ = (5.5 $\pm$ 2.8(stat.) $\pm$ 0.7(syst.))\%.

9 pages, 4 figures