Precision measurement of the three 23PJ helium fine structure intervals

T. Zelevinsky*, D. Farkas, G. Gabrielse

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

75 Scopus citations


The three 23P fine structure intervals of He4 are measured at an improved accuracy that is sufficient to test two-electron QED theory and to determine the fine structure constant α to 14 parts in 109. The more accurate determination of α, to a precision higher than attained with the quantum Hall and Josephson effects, awaits the reconciliation of two inconsistent theoretical calculations now being compared term by term. A low pressure helium discharge presents experimental uncertainties quite different than for earlier measurements and allows direct measurements of light pressure shifts.

Original languageEnglish (US)
Article number203001
JournalPhysical review letters
Issue number20
StatePublished - Nov 11 2005

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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