用 ATLAS 探测器在四轻子末态中观测纵向极化 Z 玻色子对的产生
Observation of pair production of longitudinally polarized $Z$ bosons in four-lepton final state with the ATLAS detector
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中文总结 AI 辅助
该研究利用 ATLAS 探测器及质子-质子碰撞数据，通过重建 ZZ 候选事件测量两个纵向极化 Z 玻色子产生，在特定区域测量极化分数，经与之前测量统计组合，首次观测到两个同时纵向极化的 Z 玻色子，显著性达 6.5 和 5.6 个标准差。
中文摘要 AI 辅助
利用 ATLAS 实验在质心能量√s = 13.6 TeV、积分亮度为 164 fb⁻¹ 的质子-质子碰撞数据，测量了两个纵向极化 Z 玻色子的产生。通过两个同味异号电子或μ子对重建 ZZ 候选事件。在基准相空间以及四轻子不变质量的两个区域测量了 Z 玻色子对的极化分数，结果与标准模型预测一致。与之前√s = 13 TeV 的测量进行统计组合后，首次观测到两个同时纵向极化的 Z 玻色子产生，观测和预期显著性分别为 6.5 和 5.6 个标准差。
英文摘要
The production of two longitudinally polarized $Z$ bosons is measured using proton-proton collision data recorded by the ATLAS experiment at a center-of-mass energy $\sqrt{s}=13.6$ TeV and with an integrated luminosity of 164 fb$^{-1}$. The $ZZ$ candidate events are reconstructed using two same-flavor opposite-charge electron or muon pairs. The polarization fractions of the $Z$ boson pair are measured inclusively in the fiducial phase space and also in two regions of the four-lepton invariant mass, and the results are consistent with the Standard Model predictions. After a statistical combination with a previous measurement at $\sqrt{s}=13$ TeV, the first observation of the production of two simultaneously longitudinally polarized $Z$ bosons is obtained, with observed and expected significances of 6.5 and 5.6 standard deviations, respectively.
