Enhanced n-body annihilation of dark matter and its indirect signatures
Name
13130_2019_Article_10158.pdf
Size
11.01 MB
Format
Adobe PDF
Checksum (MD5)
c5ca6f6a01e706ef155abd37a25d1f02
Author(s)
Namjoo, Mohammad Hossein
Slatyer, Tracy Robyn
Wu, Chih-Liang
Date Issued
March 2019
Journal
Journal of High Energy Physics
Publisher
Springer
Citation
Namjoo, M.H. et al. "Enhanced n-body annihilation of dark matter and its indirect signatures." Journal of High Energy Physics 2019 (March 2019): 77 © The Author(s)
Version
Final published version
Abstract
We examine the possible indirect signatures of dark matter annihilation processes with a non-standard scaling with the dark matter density, and in particular the case where more than two dark matter particles participate in the annihilation process. We point out that such processes can be strongly enhanced at low velocities without violating unitarity, similar to Sommerfeld enhancement in the standard case of two-body annihilation, potentially leading to visible signals in indirect searches. We study in detail the impact of such multi-body annihilations on the ionization history of the universe and consequently the cosmic microwave background, and find that unlike in the two-body case, the dominant signal can naturally arise from the end of the cosmic dark ages, after the onset of structure formation. We examine the complementary constraints from the Galactic Center, Galactic halo, and galaxy clusters, and outline the circumstances under which each search would give rise to the strongest constraints. We also show that if there is a population of ultra-compact dense dark matter clumps present in the Milky Way with sufficiently steep density profile, then it might be possible to detect point sources illuminated by multi-body annihilation, even if there is no large low-velocity enhancement. Finally, we provide a case study of a model where 3-body annihilation dominates the freezeout process, and in particular the resonant regime where a large low-velocity enhancement is naturally generated.
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1007/JHEP03(2019)077
