Precision measurement of Hyperfine Splitting of Positronium using the Zeeman transition

新测量了正电子的基态超细分裂，以检查过去的测量与QED预测之间的差异。在这次测量中，正电子的定时信息被用于分析。磁场的均匀性和稳定性也得到了很好的控制。得到的结果为203.3942+-0.0016(stat.)+-0.0013(sys.)GHz。该结果与QED预测偏差在1.2个标准差以内，与之前的实验平均值偏差在2.6个标准差以内。在精密测量中，正电子的热化过程的影响是不可忽略的。

The ground state hyperfine splitting of positronium is newly measured to check the discrepancy between the past measurements and the QED prediction. In this measurement, the timing information of positronium is used for the analysis. The uniformity and the stability of the magnetic field is also well-controlled.The obtained result is 203.3942+-0.0016(stat.)+-0.0013(sys.)GHz. This result favors the QED prediction within 1.2 standard deviations, and disfavors the previous experimental average by 2.6 standard deviations. It is also found that the effect of the thermalization process of positronium cannot be negligible in the precision measurement.