Measurements of branching fractions and asymmetry parameters of Ξc0→ΛK¯∗0, Ξc0→Σ0K¯∗0, and Ξc0→Σ+K∗− 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 ${\mathrm{\Xi }}_c^0\to \mathrm{\Lambda }{\overline{K}}^{\ast 0}$, ${\mathrm{\Xi }}_c^0\to {\mathrm{\Sigma }}^0{\overline{K}}^{\ast 0}$, and ${\mathrm{\Xi }}_c^0\to {\mathrm{\Sigma }}^{+}{K}^{\ast -}$ for the first time. The relative branching ratios to the normalization mode of ${\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\pi }^{+}$ are measured to be$$\begin{array}{c}\mathcal{B}\left({\mathrm{\Xi }}_c^0\to \mathrm{\Lambda }{\overline{K}}^{\ast 0}\right)/\mathcal{B}\left({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\pi }^{+}\right)=0.18\pm 0.02\left(\text{stat}.\right)\pm 0.01\left(\text{syst}.\right),\\ \mathcal{B}\left({\mathrm{\Xi }}_c^0\to {\mathrm{\Sigma }}^0{\overline{K}}^{\ast 0}\right)/\mathcal{B}\left({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\pi }^{+}\right)=0.69\pm 0.03\left(\text{stat}.\right)\pm 0.03\left(\text{syst}.\right),\\ \mathcal{B}\left({\mathrm{\Xi }}_c^0\to {\mathrm{\Sigma }}^{+}{K}^{\ast -}\right)/\mathcal{B}\left({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\pi }^{+}\right)=0.34\pm 0.06\left(\text{stat}.\right)\pm 0.02\left(\text{syst}.\right),\end{array}$$

where the uncertainties are statistical and systematic, respectively. We obtain$$\begin{array}{c}\mathcal{B}\left({\mathrm{\Xi }}_c^0\to \mathrm{\Lambda }{\overline{K}}^{\ast 0}\right)=\left(3.3\pm 0.3\left(\text{stat}.\right)\pm 0.2\left(\text{syst}.\right)\pm 1.0\left(\mathrm{ref}.\right)\right)\times {10}^{-3},\\ \mathcal{B}\left({\mathrm{\Xi }}_c^0\to {\mathrm{\Sigma }}^0{\overline{K}}^{\ast 0}\right)=\left(12.4\pm 0.5\left(\text{stat}.\right)\pm 0.5\left(\text{syst}.\right)\pm 3.6\left(\mathrm{ref}.\right)\right)\times {10}^{-3},\\ \mathcal{B}\left({\mathrm{\Xi }}_c^0\to {\mathrm{\Sigma }}^{+}{K}^{\ast 0}\right)=\left(6.1\pm 1.0\left(\text{stat}.\right)\pm 0.4\left(\text{syst}.\right)\pm 1.8\left(\mathrm{ref}.\right)\right)\times {10}^{-3},\end{array}$$

where the uncertainties are statistical, systematic, and from $\mathcal{B}\left({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\pi }^{+}\right)$, respectively. The asymmetry parameters $\alpha \left({\mathrm{\Xi }}_c^0\to \mathrm{\Lambda }{\overline{K}}^{\ast 0}\right)$ and $\alpha \left({\mathrm{\Xi }}_c^0\to {\mathrm{\Sigma }}^{+}{K}^{\ast -}\right)$ are 0.15 ± 0.22(stat.) ± 0.04(syst.) and −0.52 ± 0.30(stat.) ± 0.02(syst.), respectively, where the uncertainties are statistical followed by systematic.