New Method for Lamb-Shift Measurements
Adriaan J. van Wijngaarden, G. W. F. Drake, Péter Faragó · Physical Review Letters · 1974
The anisotropy in the quenching radiation of H atoms in the metastable $2s$ state has been studied with the aim of developing a new method for Lamb-shift measurements in hydrogenic ions. The extrapolated value of the anisotropy at zero field strength is 0.1392 \ifmmode\pm\else\textpm\fi{} 0.0015, in good agreement with the theoretical prediction 0.139 04 based on the accepted value of the Lamb shift and a consideration of hyperfine coupling effects. Our anisotropy corresponds to a Lamb shift of 1059 \ifmmode\pm\else\textpm\fi{} 13 MHz.