Nat Commun. 2025 May 28;16(1):4948. doi: 10.1038/s41467-025-59498-4.
The non-locality of quantum correlations is a fundamental feature of quantum theory. The Bell inequality serves as a benchmark for distinguishing between predictions made by quantum theory and local hidden variable theory (LHVT). Recent advancements in photon-entanglement experiments have addressed potential loopholes and have observed significant violations of variants of Bell inequality. However, examples of Bell inequalities violation in high energy physics are scarce. In this study, we utilize (10.087 ± 0.044) × 10 J/ψ events collected with the BES-III detector at the BEPCII collider, performing non-local correlation tests using the entangled hyperon pairs. The massive-entangled systems are formed and decay through strong and weak interactions, respectively. Through measurements of the angular distribution of in J/ψ → γη and subsequent cascade decays, a significant violation of LHVT predictions is observed. The exclusion of LHVT is found to be statistically significant at a level exceeding 5.2σ in the testing of three Bell-like inequalities.
量子关联的非定域性是量子理论的一个基本特征。贝尔不等式作为区分量子理论和局域隐变量理论（LHVT）预测的基准。光子纠缠实验的最新进展解决了潜在漏洞，并观察到对贝尔不等式变体的显著违背。然而，高能物理中贝尔不等式违背的例子却很稀少。在本研究中，我们利用在北京正负电子对撞机（BEPCII）上的北京谱仪III（BES-III）探测器收集的（10.087 ± 0.044）× 10⁶ J/ψ 事例，使用纠缠超子对进行非定域关联测试。大量纠缠系统分别通过强相互作用和弱相互作用形成并衰变。通过测量 J/ψ → γη 中 η 的角分布以及随后的 η 级联衰变，观察到对LHVT预测的显著违背。在对三个类贝尔不等式的测试中，发现排除LHVT在超过5.2σ 的水平上具有统计显著性。
