Astrophysical signatures of secluded dark matter
Abstract
We analyze the indirect astrophysical signatures of secluded models of WIMP dark matter, characterized by a weak-scale rate for annihilation into light MeV-scale mediators which are metastable to decay into Standard Model states. Such scenarios allow a significant enhancement of the annihilation cross section in the galactic halo relative to its value at freeze-out, particularly when the mediator is light enough for this process to proceed through radiative capture to a metastable ‘WIMP-onium’ bound state. For MeV-scale vector mediators charged under a hidden U1 gauge group, the enhanced annihilation rate leads predominantly to a sizable excess positron flux, even in the absence of astrophysical boost factors.
- Publication:
-
Physics Letters B
- Pub Date:
- January 2009
- DOI:
- 10.1016/j.physletb.2008.12.012
- arXiv:
- arXiv:0810.1502
- Bibcode:
- 2009PhLB..671..391P
- Keywords:
-
- High Energy Physics - Phenomenology;
- Astrophysics
- E-Print:
- 15 pages, 2 figures