Direct Detection of Dark Matter Electromagnetic Dipole Moments

Abstract: Dark matter candidates with electromagnetic dipole moments can arise as dark baryons in gauge-mediated or technicolor models. These dark matter candidates interact with nuclei in direct detection experiments mainly through magnetic and/or electric dipole moments. The scattering cross sections depend on the nuclear magnetic moments and nuclear charge and have an infrared enhancement compared with typical WIMP constant contact interactions, leading to distinctive nuclear recoil energy spectra. These characteristics result in an enhanced signal for the DAMA experiment compared with the CDMS or XENON experiments. The positive results of DAMA, along with the null results of CDMS and XENON, are consistent with a dark matter particle with magnetic dipole moment and a mass around ten GeV. Significant direct detection signals can arise from dipolar dark matter with mass up to of order tens of TeV.