  Recent measurements of muon spin precession and an emerging consensus for the
muon magnetic dipole moment confirm a long-standing tension within the standard
model of particle physics. We argue that axions form the dark matter in the
universe and that axions from the local dark matter halo of the galaxy are
responsible for the tension. The argument gives a percent level prediction for
the mass of the axion that can be tested by measuring the mid-infrared
electrodynamic response of a wide range of polar materials.
