Multi-component dark matter and Galactic 511 keV γ-ray emission
Abstract 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 pair...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
SpringerOpen
2025-06-01
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| Series: | Journal of High Energy Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/JHEP06(2025)102 |
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| Summary: | Abstract 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. |
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| ISSN: | 1029-8479 |