High-precision measurement of the atomic mass of the electron

摘要

电子的原子质量是基础物理学的一个关键参数。精确确定电子的原子质量是一个挑战，因为这个质量非常低。Sven Sturm及同事报告了以原子单位对电子质量所做的一个新的确定结果。他们测定了与一个参照离子(碳-12的一个裸核)相结合的一个电子的磁矩。采用最新量子电动力学理论对所获结果加以分析，产生一个质量值，其精度超过当前文献值一个数量级以上。%The quest for the value of the electron's atomic mass has been the subject of continuing efforts over the past few decades. Among the seemingly fundamental constants that parameterize the Standard Model of physics and which are thus responsible for its predictive power, the electron mass m_e is prominent, being responsible for the structure and properties of atoms and molecules. It is closely linked to other fundamental constants, such as the Rydberg constant R_∞, and the fine-structure constant α (ref. 6). However, the low mass of the electron considerably complicates its precise determination. Here we combine a very precise measurement of the magnetic moment of a single electron bound to a carbon nucleus with a state-of-the-art calculation in the framework of bound-state quantum electrodynamics. The precision of the resulting value for the atomic mass of the electron surpasses the current literature value of the Committee on Data for Science and Technology (CODATA) by a factor of 13. This result lays the foundation for future fundamental physics experiments and precision tests of the Standard Model.