  A neutral dark matter particle may possess an electric dipole moment (EDM) or
a magnetic dipole moment (MDM), so that its scattering with nuclei is governed
by electromagnetic interactions. If the moments are associated with relevant
operators of dimension-5, they may be detectable in direct search experiments.
We calculate complete expressions of the scattering cross sections and the
recoil energy spectra for dark matter with these attributes. We also provide
useful formulae pertinent to dark matter that interacts via an electric charge
form factor (CFF) which is related to the charge radius defined by an effective
dimension-6 operator. We show that a 7 GeV dark matter particle with an EDM,
MDM or CFF easily reproduces the CoGeNT excess while remaining consistent with
null searches.
