Determination of Muonium Hyperfine Structure Interval Through Measurements at Low Magnetic Fields

Abstract

The ground-state hyperfine structure interval $\Delta \nu$ of muonium has been remeasured with significantly improved accuracy through the observation of transitions between hfs states at low magnetic fields. The formation of muonium has been observed for the first time in krypton and the fractional pressure shift of $\Delta \nu$ has been measured in this gas. The average value of $\Delta \nu$ obtained from these measurements is $\Delta \nu =4463.26\mathrm{}\pm 0.04$ Mc/sec.