Self-interacting hidden sector dark matter, small scale galaxy structure anomalies, and a dark force

TL;DR

This paper proposes a hidden sector dark matter model with a dark force mediating self-interactions, explaining small-scale galaxy structure anomalies by fitting velocity-dependent cross-sections across various cosmic scales.

Contribution

It introduces a particle physics model with a feebly interacting hidden sector and a light dark photon, providing a novel explanation for galaxy-scale dark matter behavior.

Findings

Velocity-dependent dark matter cross-section fits dwarf to cluster scales.

Model consistent with relic density constraints.

Addresses small-scale structure anomalies.

Abstract

The short distance behavior of dark matter (DM) at galaxy scales exhibits several features not explained by the typical cold dark matter (CDM) with velocity-independent cross-section. We discuss a particle physics model with a hidden sector interacting feebly with the visible sector where a dark fermion self-interacts via a dark force with a light dark photon as the mediator. We study coupled Boltzmann equations involving two temperatures, one for each sector. We fit the velocity-dependent DM cross-section to the data from scales of dwarf galaxies to clusters consistent with relic density constraint.