Fermi-ball in a multicomponent dark matter framework and its gravitational wave signatures

TL;DR

This paper explores how stable Fermi-balls formed from multicomponent dark matter can significantly contribute to dark matter density and produce gravitational waves detectable by future observatories, linking dark matter physics with gravitational wave astronomy.

Contribution

It introduces a novel scenario where Fermi-balls form from coexisting minima in a two-component dark matter model, linking dark matter relics with gravitational wave signals.

Findings

Fermi-balls can account for a significant portion of dark matter relic density.

First-order phase transitions can occur due to coexisting minima in the scalar potential.

Gravitational waves from these phase transitions are detectable by BBO and U-DECIGO.

Abstract

It has been known that under-abundant dark matter density of an inert doublet can be replenished by an additional dark matter component, say, a fermion. We find that such a scenario can lead to the formation of stable Fermi-balls through coexisting minima of the finite temperature scalar potential. More importantly, we demonstrate that the Fermi-balls contribute sizeably to the dark matter relic density. In addition, the aforesaid coexisting minima open up the possibility of a first-order phase transition. This, in turn, triggers emission of gravitational waves that can be tested at the proposed BBO and U-DECIGO detectors. Therefore, the present study becomes a concrete setup to embed Fermi-balls in a realistic two-component dark matter model, and, to test the same using gravitational wave signatures.