标题： 从空间和时间类实验数据中的$η^\prime$转变形式因子 显示英文标题

标题： The $η^\prime$ transition form factor from space- and time-like experimental data

摘要： $\eta^\prime$转换形式因子在最近 BESIII 在低能和中能范围内对空间和时间类区域中的 Dalitz 衰变$\eta^\prime\to\gamma e^+e^-$首次观测的基础上重新进行了分析，使用了 Padé 近似方法。目前的分析提供了一种适合于在整个能量区域内再现测量形式因子的参数化方法，并允许提取相应的低能参数以及其在原点处的值的预测，该值与$\Gamma_{\eta^\prime\to\gamma\gamma}$相关，以及渐近极限。在与下一阶大$N_c$重夸克有效理论相容的混合方案中重新评估了$\eta$-$\eta^\prime$混合，特别关注了违反 OZI 规则的参数。 $J/\psi$，$Z\to\eta^{(\prime)}\gamma$衰变也被考虑并给出了预测。 显示英文摘要

摘要： The $\eta^\prime$ transition form factor is reanalyzed in view of the recent BESIII first observation of the Dalitz decay $\eta^\prime\to\gamma e^+e^-$ in both space- and time-like regions at low and intermediate energies using the Pad\'e approximants method. The present analysis provides a suitable parameterization for reproducing the measured form factor in the whole energy region and allows to extract the corresponding low-energy parameters together with a prediction of its values at the origin, related to $\Gamma_{\eta^\prime\to\gamma\gamma}$, and the asymptotic limit. The $\eta$-$\eta^\prime$ mixing is reassessed within a mixing scheme compatible with the large-$N_c$ chiral perturbation theory at next-to-leading order, with particular attention to the OZI-rule--violating parameters. The $J/\psi$, $Z\to\eta^{(\prime)}\gamma$ decays are also considered and predictions reported.