Continuum-Mediated Self-Interacting Dark Matter

TL;DR

This paper explores a novel continuum-mediated dark matter self-interaction model, revealing unique power-law behaviors and resonances that could explain small-scale structure anomalies in astrophysics.

Contribution

It introduces a continuum-mediated framework for dark matter self-interactions, characterized by non-integer power-law potentials and novel resonance patterns, expanding phenomenological possibilities.

Findings

Self-interaction cross section scales with a non-integer power of velocity.

Identification of Born, classical, and resonant regimes for continuum-mediated interactions.

Demonstration of the model's potential to address astrophysical small-scale anomalies.

Abstract

Dark matter may self-interact through a continuum of low-mass states. This happens if dark matter couples to a strongly-coupled nearly-conformal hidden sector. This type of theory is holographically described by brane-localized dark matter interacting with bulk fields in a slice of 5D anti-de Sitter space. The long-range potential in this scenario depends on a non-integer power of the spatial separation, in contrast to the Yukawa potential generated by the exchange of a single 4D mediator. The resulting self-interaction cross section scales like a non-integer power of velocity. We identify the Born, classical and resonant regimes and investigate them using state-of-the-art numerical methods. We demonstrate the viability of our continuum-mediated framework to address the astrophysical small-scale structure anomalies. Investigating the continuum-mediated Sommerfeld enhancement, we demonstrate that a pattern of resonances can occur depending on the non-integer power. We conclude that continuum mediators introduce novel power-law scalings which open new possibilities for dark matter self-interaction phenomenology.