The shadow of dark matter as a shadow of string theory: String origin of the dipole term

Abstract

We point out that the Kalb-Ramond field can couple to the Ramond and Neveu-Schwarz fields of superstring theory in a way that can generate a coupling of the Kalb-Ramond field to dark matter dipole moments. Electroweak dipole dark matter could then arise from the Ramond sector of superstrings with a low string scale up to 120 TeV.

Comments: 7 pages. Preprint version of paper accepted for publication in EPJ C. Contains an explanation why the new coupling preserves GSO sectors. Also includes an explanation of mode expansions of the Kalb-Ramond field in Coulomb gauge and in Lorentz gauge