Populating dark sectors with relativistic bubble walls

TL;DR

This paper explores a novel mechanism for dark matter production during first order phase transitions via relativistic bubble walls, analyzing different interaction operators and dark sector couplings, with implications for dark matter mass and velocity.

Contribution

It introduces a new production mechanism involving bubble wall collisions, analyzing scenarios with renormalisable and higher-dimensional operators, and compares with freeze-in production.

Findings

Dark matter can be much heavier than the phase transition scale.

Produced dark matter can be warm today due to high initial velocities.

Glueball dark matter exhibits distinct phenomenological properties.

Abstract

In this talk, we present a mechanism of Dark Matter production during first order phase transitions and happening via the collision of the bubble wall and plasma quanta. We will first study the possibility that the dark matter is produced via a renormalisable operator. We will observe that in this context the DM can be much heavier than the scale of the phase transition and has a large initial velocity, leading to the possibility of the DM to be warm today. We will then turn to more realistic scenarios where the Dark Matter sector is secluded and its interaction with the visible sector (including the Standard Model) originates from dimension-five and dimension-six operators. In this regime, we also find that such DM is typically heavy and warm today. We study separately the cases of weakly and strongly coupled dark sectors, where, in the latter case, we focus on glueball DM, which turns out to have very distinct phenomenological properties. For completeness, we also systematically compute the Freeze-In production of the dark sector and compare it with the bubble-plasma DM abundances. All the analytical results are collected in a table presented in this paper.