Abstract
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 language | English (US) |
|---|---|
| Article number | 203001 |
| Journal | Physical review letters |
| Volume | 95 |
| Issue number | 20 |
| DOIs | |
| State | Published - Nov 11 2005 |
ASJC Scopus subject areas
- Physics and Astronomy(all)