New Constraints on Isospin-Violating Dark Matter

TL;DR

This paper establishes new bounds on low-mass isospin-violating dark matter by analyzing gamma-ray data, constraining interaction models and informing future experimental searches.

Contribution

It derives the first direct bounds on dark matter-proton scattering cross-sections for isospin-violating models using Fermi-LAT gamma-ray data.

Findings

Bounds on annihilation cross-section for 5-20 GeV dark matter.

Constraints on dark matter-proton scattering cross-section.

Discussion of models evading current bounds.

Abstract

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.