A Practical and Consistent Parametrization of Dark Matter Self-Interactions

Understand

Self-interacting dark matter has been proposed to explain the apparent mass deficit in astrophysical small-scale halos, while observations from galaxy clusters suggest that the corresponding cross section depends on the velocity.

• Accounting for this is often believed to be highly model-dependent with studies mostly focusing on scenarios with light mediators.
• Based on the effective-range formalism, in this work we point out a model-independent approach which accurately approximates the velocity dependence of the self-interaction cross section with only two parameters.
• We illustrate how this parameterization can be simultaneously interpreted in various well-motivated scenarios, including self-interactions induced by Yukawa forces, Breit-Wigner resonances and bound states.