物理学家在理论计算上解决了困扰该领域的μ子谜团，但这一突破反而暴露出实验数据间的深层不一致。[1]μ子在磁场中的摆动行为（g-2值）长期显示出百万分之一的偏差，曾暗示可能存在未知粒子。[1]2021年，采用格点QCD计算方法的BMW团队达到百亿分之一的计算精度，得出的结果与费米实验室的测量数据相符。[1]
然而，这一一致性反而揭示了另一个问题：基于电子-正电子碰撞数据推导的传统预测与新的格点QCD结果产生了矛盾。[1]物理学家正在调查西伯利亚VEPP-2000对撞机等多个实验设施的数据，以查明症结所在。[1]该对撞机在2010年安装新探测器后，2023年发布的π介子产生率测量结果与之前的测量显著不同，而BMW团队2024年的格点模拟计算结果与这一最新测量基本一致。[1]
伦敦大学学院高级研究员Alex Keshavarzi表示，"测量μ子g-2是了解宇宙中有多少粒子存在的代理方法"，并指出"没有任何测量被审视得这么彻底"。[1]目前尚不确定是否存在新粒子的发现，还是实验程序本身需要改进。
Physicists have resolved a long-standing theoretical puzzle about how muons behave in magnetic fields, but the solution has unveiled a deeper contradiction in their data.[1] In 2021, the BMW team used lattice QCD calculations to achieve precision at the billionths level, obtaining results that aligned with measurements from Fermilab.[1] However, this new theoretical framework contradicts predictions derived from traditional methods based on electron-positron collision data.[1]
The muon's g-2 value has exhibited a deviation of one part per million over the past 25 years, suggesting the possible existence of previously unknown particles.[1] To investigate whether new particles are involved or whether experimental procedures contain errors, physicists are now scrutinizing data from multiple experimental facilities, including the VEPP-2000 collider in Siberia.[1] The VEPP-2000 collider released measurements of pion production rates in 2023 that differed significantly from its previous measurements, following the installation of new detectors in 2010.[1] The BMW team's 2024 lattice simulation calculations are largely consistent with these latest pion production rate findings.[1]
According to Alex Keshavarzi, a senior research fellow at University College London, measuring the muon's g-2 serves as a proxy method for understanding how many particles exist in the universe.[1] Keshavarzi also noted that no measurement has been scrutinized as thoroughly as this one.[1]