Determination of the Hydrogenic-Carbon Lamb Shift via2S12Metastable Quenching

Abstract

We have measured the Lamb shift in the $n=2\mathrm{}$ state of hydrogenic carbon-12. The result is 780.1 ± 8.0 GHz as compared with the quantum-electrodynamic calculation of 783.7 ± 0.24 GHz. The ratio of the electron-pickup cross section to the $2S_{\frac{1}{2}}$ metastable state to the total electron-pickup cross section has also been determined as 0.022 ± 0.010 in argon at 25 MeV.