Dark-matter electric and magnetic dipole moments
We consider the consequences of a neutral dark-matter particle with a nonzero electric and/or magnetic dipole moment. Theoretical constraints, as well as constraints from direct searches, precision tests of the standard-model, the cosmic microwave background and matter power spectra, and cosmic gamma rays, are included. We find that a relatively light particle with mass between an MeV and a few GeV and an electric or magnetic dipole as large as ~3 x 10 to the -16 e cm (roughly 1.6 x 10 to the -5 μB) satisfies all experimental and observational bounds. Some of the remaining parameter space may be probed with forthcoming more sensitive direct searches and with the Gamma-Ray Large Area Space Telescope.
Additional Information© 2004 The American Physical Society. Received: 17 June 2004; published: 6 October 2004. We thank S. Golwala, J. Albert, M. Zaldarriaga, and R. Shrock for useful discussions. K.S. acknowledges the support of the Canadian NSERC. This work was supported in part by NASA NAG5-9821 and DoE DE-FG03-92-ER40701 (at Caltech) and NSF PHY-0099543 (at Dartmouth). M.D. and R.C. thank Caltech for hospitality during the course of this investigation.
Published - SIGprd04.pdf