Measurement of the 1s-2s energy interval in muonium

Abstract

The 1s-2s interval has been measured in the muonium ({$\hat{I}{¼}^{+}{e}^{-}$}) atom by Doppler-free two-photon laser spectroscopy. The frequency separation of the states was determined to be 2 455 528 941.0(9.8) MHz in good agreement with quantum electrodynamics. The muon-electron mass ratio can be extracted and is found to be 206.768 38(17). The result may be interpreted as measurement of the muon-electron charge ratio as $-1-1.1(2.1)\cdot 10^{-9}$.

12 Pages, 4 figures