We derive bounds on the dark matter annihilation cross-section for low-mass (5-20 GeV) dark matter annihilating primarily to up or down quarks, using the Fermi-LAT bound on gamma-rays from Milky Way satellites. For models in which dark matter-Standard Model interactions are mediated by particular contact operators, we show that these bounds can be directly translated into bounds on the dark matter-proton scattering cross-section. For isospin-violating dark matter, these constraints are tight enough to begin to constrain the parameter-space consistent with experimental signals of low-mass dark matter. We discuss possible models that can evade these bounds.
@article{arxiv.1112.4849,
title = {New Constraints on Isospin-Violating Dark Matter},
author = {Jason Kumar and David Sanford and Louis E. Strigari},
journal= {arXiv preprint arXiv:1112.4849},
year = {2013}
}
Comments
6 pages, 2 figures, LaTeX, some clarifications and minor errors corrected, citations added