Hot and heavy dark matter from a weak scale phase transition

TL;DR

This paper explores how non-adiabatic production of heavy dark matter during a weak scale phase transition results in high velocities, affecting cosmic structures and offering new observational avenues through galaxy surveys, gravitational waves, and decay signals.

Contribution

It introduces a mechanism where dark matter produced in a phase transition gains velocity boosts, impacting structure formation and linking to gravitational wave signals.

Findings

Dark matter with masses around 10^8 - 10^9 GeV can be detected via suppressed matter power spectrum.

Phase transition at the edge of supercooling influences dark matter velocity and distribution.

Potential observational signatures include galaxy surveys, Lyman-alpha, lensing, and gravitational waves.

Abstract

We point out that dark matter which is produced non-adiabatically in a phase transition (PT) with fast bubble walls receives a boost in velocity which leads to long free-streaming lengths. We find that this could be observed via the suppressed matter power spectrum for dark matter masses around $10^8 - 10^9$ GeV and energy scales of the PT around $10^{2} - 10^3$ GeV. The PT should take place at the border of the supercooled regime, i.e. approximately when the Universe becomes vacuum dominated. This work offers novel physics goals for galaxy surveys, Lyman-$\alpha$, stellar stream, lensing, and 21-cm observations, and connects these to the gravitational waves from such phase transitions, and more speculatively to possible telescope signals of heavy dark matter decay.