Reexamination of the helium fine structure

In order to explain discrepancies between theoretical predictions and experimental data for the helium fine structure, we check and recalculate all theoretical contributions up to orders mα⁷ and m²/Mα⁶. The previous result for the mα⁷ correction is improved by a more accurate calculation of relativistic corrections to the Bethe logarithm. The theoretical values of the 2 ³P₀-2 ³P₁ and 2 ³P₁-2 ³P₂ fine-structure intervals in helium are, correspondingly, ν₀₁=29 616 946.2(1.6) kHz and ν₁₂=2 291 177.3(1.6) kHz, with the uncertainties being due to higher-order effects. For the small interval ν₁₂, the theoretical value agrees with the experimental data, whereas for the large interval ν₀₁, a discrepancy of about three standard deviations is present.