Geometric foundation of the magnetic dipole moment

The observed value of the magnetic dipole moment of the electron is much larger than that allowed by electromagnetic theory. In particular, Maxwell's equations, together with the known upper bound on the size of the electron predict a magnetic moment much smaller than the observed one, even if the particle is rotating at the speed of light! In gravitation with an asymmetric connection, the intrinsic spin of an elementary particle gives rise to torsion. It is shown here that this source, spin, can also give rise to the observed magnetic dipole moment of the electron, and do so with no moving parts.