RIKEN, Ulmer Initiative Research Unit, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan.
Nat Commun. 2017 Jan 18;8:14084. doi: 10.1038/ncomms14084.
Our current understanding of the Universe comes, among others, from particle physics and cosmology. In particle physics an almost perfect symmetry between matter and antimatter exists. On cosmological scales, however, a striking matter/antimatter imbalance is observed. This contradiction inspires comparisons of the fundamental properties of particles and antiparticles with high precision. Here we report on a measurement of the g-factor of the antiproton with a fractional precision of 0.8 parts per million at 95% confidence level. Our value /2=2.7928465(23) outperforms the previous best measurement by a factor of 6. The result is consistent with our proton g-factor measurement g/2=2.792847350(9), and therefore agrees with the fundamental charge, parity, time (CPT) invariance of the Standard Model of particle physics. Additionally, our result improves coefficients of the standard model extension which discusses the sensitivity of experiments with respect to CPT violation by up to a factor of 20.
我们目前对宇宙的理解来自于粒子物理学和宇宙学。在粒子物理学中，物质和反物质之间存在着几乎完美的对称。然而，在宇宙学尺度上，却观察到了明显的物质/反物质失衡。这种矛盾激发了人们对粒子和反粒子基本性质进行高精度比较。在这里，我们报告了一项对反质子 g 因子的测量结果，在 95%置信水平下的分数精度为 0.8 百万分之一。我们的值 /2=2.7928465(23)超过了之前最好的测量值的 6 倍。该结果与我们的质子 g 因子测量值 g/2=2.792847350(9)一致，因此与粒子物理学标准模型的基本电荷、宇称、时间（CPT）不变性一致。此外，我们的结果改进了标准模型扩展的系数，该扩展讨论了实验对 CPT 破坏的敏感性，提高了多达 20 倍。
