X-ray Lines from Dark Matter: The Good, The Bad, and The Unlikely

Abstract

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 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 $\lesssim 10^6$ GeV.

14 pages, 4 figures; updated to match JCAP published version

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Cited by in corpus (33)

• Physics potential of the International Axion Observatory (IAXO)
• Discovery of a 3.5 keV line in the Galactic Center and a Critical Look at the Origin of the Line Across Astronomical Targets
• Dark-matter bound states from Feynman diagrams
• A 3.55 keV Photon Line and its Morphology from a 3.55 keV ALP Line
• SIMPle Dark Matter: Self-Interactions and keV Lines
• Self-Scattering for Dark Matter with an Excited State
• Generating X-ray lines from annihilating dark matter
• 3.5 keV X-rays as the "21 cm line" of dark atoms, and a link to light sterile neutrinos
• 3.55 keV photon lines from axion to photon conversion in the Milky Way and M31
• Nonthermal Two Component Dark Matter Model for Fermi-LAT $\gamma$-ray excess and 3.55 keV X-ray Line
• 7 keV Scalar Dark Matter and the Anomalous Galactic X-ray Spectrum
• keV Photon Emission from Light Nonthermal Dark Matter
• A Fresh Look at keV Sterile Neutrino Dark Matter from Frozen-In Scalars
• Signals from dark atom formation in halos
• X-ray line in Radiative Neutrino Model with Global $U(1)$ Symmetry
• The 3.5 keV X-ray line signal from decaying moduli with low cutoff scale
• Consistency of dark matter interpretations of the 3.5 keV X-ray line
• Decaying Vector Dark Matter as an Explanation for the 3.5 keV Line from Galaxy Clusters
• Nonabelian dark matter models for 3.5 keV X-rays
• SUSY in the sky or a keV signature of sub-GeV gravitino dark matter
• 3.5-keV X-ray line from nearly-degenerate WIMP dark matter decays
• X-ray Line from the Dark Transition Electric Dipole
• Exploring X-Ray Lines as Scotogenic Signals
• Non-abelian Dark Matter Solutions for Galactic Gamma-ray Excess and Perseus 3.5 keV X-ray Line
• Displaced Vertices from X-ray Lines
• 3.5 keV X-ray line and R-Parity Conserving Supersymmetry
• A 3.55 keV Line from Exciting Dark Matter without a Hidden Sector
• ${\nu }_R$ dark matter-philic Higgs for 3.5 keV X-ray signal
• Non-relativistic and potential non-relativistic effective field theories for scalar mediators
• 3.5 keV Galactic Emission Line as a Signal from the Hidden Sector
• Supersymmetric Higgs-portal and X-ray lines
• 7 keV sterile neutrino Dark Matter in extended seesaw framework
• EDGES of the dark forest: A new absorption window into the composite dark matter and large scale structure