Muon g-2 Experiments as Dark Matter Detectors

  • Feb. 11, 2021, 2:30 pm US/Central
  • Ryan Janish, FNAL
  • video
  • slides

We propose extending the search for dark matter (DM) by considering muon spin targets.  An ultralight DM background may apply an oscillating torque to muon spins, resulting in novel precession trajectories.  A time-resolved analysis of muon precession data from the upcoming Fermilab and J-PARC g-2 experiments and future frozen spin EDM measurements are sensitive to this signal, and immediate constraints may also be placed using existing g-2 measurements.  In addition, some DM candidates alter precession primarily through a shifted precession frequency, i.e. they provide an apparent contribution to the muon magnetic dipole moment which depends on the local DM density.  We find that the current muon g-2 anomaly can be explained by pseudoscalar DM which induces an oscillating electric dipole moment for the muon.  This explanation may be verified with a time-resolved analysis.