Self-scattering for Dark Matter with an excited state
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Slatyer_Self-scattering.pdf
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3.57 MB
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Author(s)
Schutz, Katelin
Slatyer, Tracy Robyn
Date Issued
January 2015
Journal
Journal of Cosmology and Astroparticle Physics
Publisher
IOP Publishing
Citation
Schutz, Katelin, and Tracy R. Slatyer. “Self-Scattering for Dark Matter with an Excited State.” Journal of Cosmology and Astroparticle Physics 2015, no. 01 (January 14, 2015): 021–021.
Version
Final published version
Abstract
Self-interacting dark matter scenarios have recently attracted much attention, as a possible means to alleviate the tension between N-body simulations and observations of the dark matter distribution on galactic and sub-galactic scales. The presence of internal structure for the dark matter—for example, a nearly-degenerate state in the spectrum that could decay, or be collisionally excited or de-excited—has also been proposed as a possible means to address these discrepancies. Such internal structure can be a source of interesting signatures in direct and indirect dark matter searches, for example providing a novel explanation for the 3.5 keV line recently observed in galaxies and galaxy clusters. We analyze a simple model of dark matter self-scattering including a nearly-degenerate excited state, and develop an accurate analytic approximation for the elastic and inelastic s-wave cross sections, which is valid outside the perturbative regime provided the particle velocity is sufficiently low (this condition is also required for the s-wave to dominate over higher partial waves). We anticipate our results will be useful in incorporating inelastic self-scattering into N-body simulations, in order to study the quantitative impact of nearly-degenerate states in the dark matter spectrum on galactic structure and dynamics, and in computing the indirect signatures of multi-state dark matter.
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
Massachusetts Institute of Technology. Department of Physics
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DOI of Published Version
https://doi.org/10.1088/1475-7516/2015/01/021
