Year: 2025
Type: article
Abstract: A bstract We study multi-component dark matter scenarios and the Galactic 511 keV γ -ray emission line signal in the framework of a local, dark U(1) D extension of the Standard Model. A light vector dark matter particle associated with the dark U(1) D may decay and annihilate to electron-positron pairs. The produced positrons may in turn form positroniums that subsequently annihilate to two photons, accounting for the observed line signal of the Galactic 511 keV γ -ray emission. Three scenarios are investigated. First, we consider the minimal U(1) D extension where a dark gauge boson and a dark Higgs boson are newly introduced to the particle content. As a second scenario, we consider WIMP-type dark matter with the introduction of an extra dark fermion which, in addition to the dark gauge boson, may contribute to the dark matter relic abundance. It is thus a multi-component dark matter scenario with a UV-complete dark U(1) D symmetry. In particular, the vector dark matter may account for a small fraction of the total dark matter relic abundance. Finally, we consider the scenario where the dark matter particles are of the FIMP-type. In this case, both the light vector and fermion dark matter particles may be produced via the freeze-in and super-WIMP mechanisms. Considering theoretical and observational constraints, we explore the allowed parameter space where the Galactic 511 keV γ -ray line signal and the dark matter relic can both be explained. We also discuss possible observational signatures.
Source: Journal of High Energy Physics
Authors: Sarif Khan, Jinsu Kim, Jinsu Kim, Jongkuk Kim, Jongkuk Kim, Pyungwon Ko
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
Awards: G2179881863, G3018278954, G7556027042
OpenAlex ID: W4411255693