What is g-2?

You want to know what g-2 is? Well, g is the gyromagnetic ratio for the electron, which is the actual magnetic moment divided by what it would be if it were a classical ball of spinning charge with the same angular momentum. Two is the value it would have for the Dirac equation (relativistic quantum mechanics, but without radiative corrections). g-2 is the correction due to quantum electrodynamics, and is called the anomalous magnetic moment of the electron.


Last modified: May 24, 1997

James P. Sethna, sethna@lassp.cornell.edu

Statistical Mechanics: Entropy, Order Parameters, and Complexity, now available at Oxford University Press (USA, Europe).