Bouncing pNGB Dark Matter via a Fermion Dark Matter

TL;DR

This paper investigates a dual dark matter model involving a pNGB and a fermion, both interacting via Higgs portals, focusing on their thermal history, collider constraints, and detection prospects.

Contribution

It introduces a novel scenario with both a pNGB and a fermion as dark matter candidates, analyzing their combined thermal freeze-out and detection signatures.

Findings

The model satisfies relic abundance constraints.

The pNGB exhibits a bouncing behavior before decoupling.

Collider and detection bounds are compatible with the scenario.

Abstract

In addition to the Standard Model, the introduction of a singlet complex scalar field that acquires vacuum expectation value may give rise to a cosmologically stable pseudo-Nambu-Goldstone boson (pNGB), a suitable dark matter (DM) candidate. This work extends this scenario by including a second cosmologically stable particle: a fermion singlet. The pNGB and the new fermion can be regarded as DM candidates simultaneously, both interacting with the Standard Model through Higgs portals via two non-degenerate Higgs bosons. We explore the thermal freeze-out of this scenario, with particular emphasis on the increasing yield of the pNGB before it completely decouples (recently called Bouncing DM). We test the model under collider bounds, relic abundance, and direct detection, and we explore some indirect detection observables today.