The magnet in the electron

The best measurement ever of the electron's magnetic moment allows us to re-evaluate the fine-structure constant and put quantum electrodynamics to the ultimate test, explains Gerald Gabrielse. In the February issue of Physics World, Gerald Gabrielse explains his team's ingenious method to measure the magnetic moment of the electron, and how their findings have let them determine the fine-structure constant - a fundamental constant of nature - with an accuracy of about 10 times better than any rival method. The work could even help physicists to test if the electron has any internal structure. (U.K.)