AI 中文总结
该研究利用LHC重构的顶夸克对两量子比特自旋密度矩阵，通过其单圈阶CP奇性自旋关联，得到与直接产生过程相当的顶夸克汤川耦合CP破坏互补约束。
AI 中文摘要
大型强子对撞机（LHC）的测量如今可重构顶夸克对（$t\bar{t}$）的两量子比特自旋密度矩阵的全部15个参数，这相当于对该对粒子进行完整的量子层析成像。我们证明，该数据可约束顶夸克汤川耦合中的CP破坏，该耦合在单圈阶进入密度矩阵，产生CP奇性的自旋关联且不影响总截面。利用首个完整的重整化单圈密度矩阵及实验协方差，我们得到的互补约束可与直接树级$t\bar{t}H$和$tH$产生过程的约束相媲美。
英文摘要
LHC measurements now reconstruct all fifteen parameters of the $t\bar t$ two-qubit spin density matrix, which amounts to a full quantum tomography of the pair. We show that this data constrains CP violation in the top-Yukawa coupling. The coupling enters the density matrix at one loop and produces spin correlations that are odd under CP and do not affect the cross section. Using the first complete renormalized one-loop density matrix and the experimental covariance, we obtain complementary constraints comparable to those from direct tree-level $t\bar t H$ and $tH$ production.
Comments8 pages, 3 figures
