AI 中文总结
研究未来轻子对撞机中Z′介导的tˉt产生的量子自旋关联，通过自旋密度矩阵分析相关过程，关注量子信息可观测量，考虑多种电荷分配，表明电子束极化可控制轻子电荷，量子自旋可观测量能提供互补信息。
AI 中文摘要
我们研究了在标准模型无反常的一般U(1)扩展存在中性规范玻色子的情况下，未来轻子对撞机上顶夸克对产生中的量子自旋关联。通过包括γ、Z和Z′交换及其干涉的自旋密度矩阵分析了过程ℓ+ℓ−→tˉt（其中ℓ=e、μ）。我们关注量子信息可观测量，如充分纠缠标记Dmin、并发度、纯度和最大Clauser-Horne-Shimony-Holt（CHSH）参数，并将它们的行为与传统速率信息进行比较。在U(1)X框架内，我们考虑几种代表性电荷分配，研究不同手征结构如何影响这些可观测量，特别强调Z′共振区域和极化e−e+碰撞，其中两种允许的初态螺旋度配置可被选择性增强。我们表明电子束极化直接控制各种U(1)X场景中的左右手轻子电荷。这些结果表明，在寻找手征中性规范相互作用时，量子自旋可观测量提供了与截面和角分布互补的信息。
英文摘要
We study quantum spin correlations in top-quark pair production at future lepton colliders in the presence of a neutral gauge boson from anomaly-free general $U(1)$ extensions of the Standard Model. The process $\ell^+\ell^-\to t\bar t$, with $\ell=e,μ$, is analyzed through the spin-density matrix including $γ$, $Z$ and $Z^\prime$ exchange and their interference. We focus on quantum-information observables such as the sufficient entanglement marker $\mathcal{D}_{\min}$, concurrence, purity and the maximal Clauser-Horne-Shimony-Holt (CHSH) parameter, and compare their behavior with conventional rate information. Within the $U(1)_X$ framework, we consider several representative charge assignments to investigate how different chiral structures influence these observables, with particular emphasis on the $Z^\prime$ resonance region and polarized $e^-e^+$ collisions, where the two allowed initial-state helicity configurations can be selectively enhanced. We show that electron-beam polarization provides a direct handle on the left- and right-handed lepton charges of various $U(1)_X$ scenarios. These results demonstrate that quantum spin observables provide information complementary to cross sections and angular distributions in searches for chiral neutral gauge interactions.
Comments20 pages, 10 figures, and 3 tables
