Measurements of branching fractions and asymmetry parameters of $\hat{I}{ž}_c^0\to \hat{I}›{\bar{K}}^{\ast 0}$, $\hat{I}{ž}_c^0\to \hat{I}{\pounds }^0{\bar{K}}^{\ast 0}$, and $\hat{I}{ž}_c^0\to \hat{I}{\pounds }^{+}{K}^{\ast -}$ decays at Belle

Abstract

Using a data sample of 980 fb${}^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider, we study the processes of $\hat{I}{ž}_c^0\to \hat{I}›{\bar{K}}^{\ast 0}$, $\hat{I}{ž}_c^0\to \hat{I}{\pounds }^0{\bar{K}}^{\ast 0}$, and $\hat{I}{ž}_c^0\to \hat{I}{\pounds }^{+}{K}^{\ast -}$ for the first time. The relative branching ratios to the normalization mode of $\hat{I}{ž}_c^0\to \hat{I}{ž}^{-}\ddot{I}{€}^{+}$ are measured to be $${\cal B}(Ξ^0_c\to Λ\bar K^{*0})/{\cal B}(\xic\to Ξ^-π^+)=0.18\pm0.02({\rm stat.})\pm0.01({\rm syst.}),$$ $${\cal B}(Ξ^0_c\to Σ^0\bar K^{*0})/{\cal B}(\xic\to Ξ^-π^+)=0.69\pm0.03({\rm stat.})\pm0.03({\rm syst.}),$$ $${\cal B}(Ξ^0_c\to Σ^+K^{*-})/{\cal B}(\xic\to Ξ^-π^+)=0.34\pm0.06({\rm stat.})\pm0.02({\rm syst.}),$$ where the uncertainties are statistical and systematic, respectively. We obtain %measure the branching fractions of $\hat{I}{ž}_c^0\to \hat{I}›{\bar{K}}^{\ast 0}$, $\hat{I}{ž}_c^0\to \hat{I}{\pounds }^0{\bar{K}}^{\ast 0}$, and $\hat{I}{ž}_c^0\to \hat{I}{\pounds }^{+}{K}^{\ast -}$ to be $$\mathcal{B}(\hat{I}{ž}_c^0\to \hat{I}›{\bar{K}}^{\ast 0})=(3.3\pm 0.3(stat.)\pm 0.2(syst.)\pm 1.0(ref.))\times 10^{-3},$$ $$\mathcal{B}(\hat{I}{ž}_c^0\to \hat{I}{\pounds }^0{\bar{K}}^{\ast 0})=(12.4\pm 0.5(stat.)\pm 0.5(syst.)\pm 3.6(ref.))\times 10^{-3},$$ $$\mathcal{B}(\hat{I}{ž}_c^0\to \hat{I}{\pounds }^{+}{K}^{\ast -})=(6.1\pm 1.0(stat.)\pm 0.4(syst.)\pm 1.8(ref.))\times 10^{-3},$$ where the uncertainties are statistical, systematic, and from ${\cal B}(\xic \to Ξ^-π^+)$, respectively. The asymmetry parameters $\hat{I}\pm (\hat{I}{ž}_c^0\to \hat{I}›{\bar{K}}^{\ast 0})$ and $\hat{I}\pm (\hat{I}{ž}_c^0\to \hat{I}{\pounds }^{+}{K}^{\ast -})$ are $0.15\pm 0.22(stat.)\pm 0.04(syst.)$ and $-0.52\pm 0.30(stat.)\pm 0.02(syst.)$, respectively, where the uncertainties are statistical followed by systematic.

18 pages, 4 figures, 8 tables, accepted for publication in JHEP