Measurement of the 2S hyperfine interval in atomic hydrogen.
An optical measurement of the 2S hyperfine interval in atomic hydrogen using two-photon spectroscopy of the 1S-2S transition gives a value of 177 556 834.3(6.7) Hz. The uncertainty is 2.4 times smaller than achieved by our group in 2003 and more than 4 times smaller than for any independent radio-frequency measurement. The specific combination of the 2S and 1S hyperfine intervals predicted by QED theory 8fHFS(2S)-fHFS(1S)=48 953(3) Hz is in good agreement with the value of 48 923(54) Hz obtained from this experiment.
Kolachevsky
N
N
Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany.
Matveev
A
A
Alnis
J
J
Parthey
C G
CG
Karshenboim
S G
SG
Hänsch
T W
TW