Eighth-Order Anomalous Magnetic Moment of the Electron

A very preliminary value $(-0.8\mathrm{}\pm 2.5){\left(\frac{\alpha }{\pi }\right)}^4$ is reported for the complete eighth-order QED contribution to the electron anomalous magnetic moment. The large error reflects the difficulty in evaluating the huge integrals involved and will be reduced in the future. Theory and experiment agree within 2 standard deviations. The current result enables us to determine, in a manner based solely upon elementary-particle physics, the fine-structure constant $\alpha$ to an accuracy of 0.08 ppm.