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Title: X-ray lines from dark matter: the good, the bad, and the unlikely

We consider three classes of dark matter (DM) models to account for the recently observed 3.5 keV line: metastable excited state DM, annihilating DM, and decaying DM. We study two examples of metastable excited state DM. The first, millicharged composite DM, has both inelasticity and photon emission built in, but with a very constrained parameter space. In the second example, up-scattering and decay come from separate sectors and is thus less constrained. The decay of the excited state can potentially be detectable at direct detection experiments. However we find that CMB constraints are at the border of excluding this as an interpretation of the DAMA signal. The annihilating DM interpretation of the X-ray line is found to be in mild tension with CMB constraints. Lastly, a generalized version of decaying DM can account for the data with a lifetime exceeding the age of the Universe for masses ∼<10{sup 6} GeV.
Authors:
; ; ;  [1]
  1. CP"3-Origins and Danish Institute for Advanced Study DIAS, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark)
Publication Date:
OSTI Identifier:
22373564
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 05; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DECAY; EXCITED STATES; KEV RANGE 01-10; MASS; NONLUMINOUS MATTER; PHOTON EMISSION; POTENTIALS; SCATTERING; SIGNALS; SPACE; UNIVERSE; X RADIATION