Measurements of branching fractions and asymmetry parameters of ${\Xi }_c^0\to \Lambda {\bar{K}}^{\ast 0}$, ${\Xi }_c^0\to {\Sigma }^0{\bar{K}}^{\ast 0}$, and ${\Xi }_c^0\to {\Sigma }^{+}{K}^{\ast -}$ 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 ${\Xi }_c^0\to \Lambda {\bar{K}}^{\ast 0}$, ${\Xi }_c^0\to {\Sigma }^0{\bar{K}}^{\ast 0}$, and ${\Xi }_c^0\to {\Sigma }^{+}{K}^{\ast -}$ for the first time. The relative branching ratios to the normalization mode of ${\Xi }_c^0\to {\Xi }^{-}{\pi }^{+}$ are measured to be $$\mathcal{B}({\Xi }_c^0\to \Lambda {\bar{K}}^{\ast 0})/\mathcal{B}(\text{xic}\to {\Xi }^{-}{\pi }^{+})=0.18\pm 0.02(stat.)\pm 0.01(syst.),$$ $$\mathcal{B}({\Xi }_c^0\to {\Sigma }^0{\bar{K}}^{\ast 0})/\mathcal{B}(\text{xic}\to {\Xi }^{-}{\pi }^{+})=0.69\pm 0.03(stat.)\pm 0.03(syst.),$$ $$\mathcal{B}({\Xi }_c^0\to {\Sigma }^{+}{K}^{\ast -})/\mathcal{B}(\text{xic}\to {\Xi }^{-}{\pi }^{+})=0.34\pm 0.06(stat.)\pm 0.02(syst.),$$ where the uncertainties are statistical and systematic, respectively. We obtain %measure the branching fractions of ${\Xi }_c^0\to \Lambda {\bar{K}}^{\ast 0}$, ${\Xi }_c^0\to {\Sigma }^0{\bar{K}}^{\ast 0}$, and ${\Xi }_c^0\to {\Sigma }^{+}{K}^{\ast -}$ to be $$\mathcal{B}({\Xi }_c^0\to \Lambda {\bar{K}}^{\ast 0})=(3.3\pm 0.3(stat.)\pm 0.2(syst.)\pm 1.0(ref.))\times 10^{-3},$$ $$\mathcal{B}({\Xi }_c^0\to {\Sigma }^0{\bar{K}}^{\ast 0})=(12.4\pm 0.5(stat.)\pm 0.5(syst.)\pm 3.6(ref.))\times 10^{-3},$$ $$\mathcal{B}({\Xi }_c^0\to {\Sigma }^{+}{K}^{\ast -})=(6.1\pm 1.0(stat.)\pm 0.4(syst.)\pm 1.8(ref.))\times 10^{-3},$$ where the uncertainties are statistical, systematic, and from $\mathcal{B}(\text{xic}\to {\Xi }^{-}{\pi }^{+})$, respectively. The asymmetry parameters $\alpha ({\Xi }_c^0\to \Lambda {\bar{K}}^{\ast 0})$ and $\alpha ({\Xi }_c^0\to {\Sigma }^{+}{K}^{\ast -})$ 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.

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