Determination of the Fine Structure Constant Using Helium Fine Structure

We measure 31 908 131.25(30) kHz for the 2(3)P J = 0 to 2 fine structure interval in helium. The difference between this and theory to order m alpha(7) (20 Hz numerical uncertainty) implies 0.22(30) kHz for uncalculated terms. The measurement is performed by using atomic beam and electro-optic laser techniques. Various checks include a (3)He 2(3)S hyperfine measurement. We can obtain an independent value for the fine structure constant alpha with a 5 ppb experimental uncertainty. However, dominant m alpha(8) terms (potentially 1.2 kHz) limit the overall uncertainty to a less competitive 20 ppb in alpha.