Title: Evidence of Transverse Polarization of $Ξ^0$ Hyperon in $ψ(3686)\rightarrowΞ^0\barΞ^0$ Show Chinese title

Title: $Ξ^0$奇子在$ψ(3686)\rightarrowΞ^0\barΞ^0$中的横向极化的证据

Abstract: Using $(2.712\pm0.014)\times10^{9}$ $\psi(3686)$ events collected with the BESIII detector at the BEPCII collider, we report an evidence of $\Xi^{0}$ transverse polarization with a significance of 4.4$\sigma$, and a precise measurement of the branching fraction of $\psi(3686)\to\Xi^{0}\bar\Xi^{0}$. The weak decay parameters ($\phi_{\Xi^0/\bar{\Xi}^{0}}$, $\alpha_{\Xi^0/\bar{\Xi}^{0}}$) and the angular distribution ($\alpha_{\psi}$) are also measured with higher precision compared to the previous measurements. Furthermore, two the $C\!P$ observables are also determined to be $A^{\Xi^0}_{C\!P} = -0.014 \pm 0.030 \pm 0.010$ and $\Delta\phi^{\Xi^0}_{C\!P} = 0.000 \pm 0.028 \pm 0.003$ rad, which are still consistent with $C\!P$ conservation at 1$\sigma$ level under the current statistics. Show Chinese abstract

Abstract: 使用在BEPCII对撞机上用BESIII探测器收集的$(2.712\pm0.014)\times10^{9}$ $\psi(3686)$ 事件，我们报告了具有4.4$\sigma$显著性的$\Xi^{0}$横向极化证据，并对$\psi(3686)\to\Xi^{0}\bar\Xi^{0}$的分支比进行了精确测量。 弱衰变参数 ($\phi_{\Xi^0/\bar{\Xi}^{0}}$,$\alpha_{\Xi^0/\bar{\Xi}^{0}}$) 和角分布 ($\alpha_{\psi}$) 也相较于之前的测量具有更高的精度。 此外，两个 $C\!P$ 观测量也被确定为 $A^{\Xi^0}_{C\!P} = -0.014 \pm 0.030 \pm 0.010$ 和 $\Delta\phi^{\Xi^0}_{C\!P} = 0.000 \pm 0.028 \pm 0.003$ 弧度，这在当前统计下仍与 $C\!P$ 守恒在 1 $\sigma$ 水平上一致。