Is dark matter with long-range interactions a solution to all small-scale problems of \Lambda CDM cosmology?

TL;DR

This paper explores a class of dark matter models with long-range, velocity-dependent self-interactions that could resolve small-scale structure issues in DM cosmology, aligning observations with theoretical predictions.

Contribution

It introduces a simple dark matter model with velocity-dependent self-interactions mediated by a light vector, potentially solving multiple small-scale problems simultaneously.

Findings

Model can address dwarf galaxy abundance issues.

Model explains internal density structures of satellites.

Long-range interactions improve DM small-scale predictions.

Abstract

The cold dark matter (DM) paradigm describes the large-scale structure of the universe remarkably well. However, there exists some tension with the observed abundances and internal density structures of both field dwarf galaxies and galactic satellites. Here, we demonstrate that a simple class of DM models may offer a viable solution to all of these problems simultaneously. Their key phenomenological properties are velocity-dependent self-interactions mediated by a light vector messenger and thermal production with much later kinetic decoupling than in the standard case.