The 7 keV axion dark matter and the X-ray line signal

Tetsutaro Higaki, Kwang Sik Jeong, Fuminobu Takahashi

Research output: Contribution to journalArticlepeer-review

80 Citations (Scopus)


We propose a scenario where the saxion dominates the energy density of the Universe and reheats the standard model sector via the dilatonic coupling, while its axionic partner contributes to dark matter decaying into photons via the same operator in supersymmetry. Interestingly, for the axion mass m a ≃ 7keV and the decay constant f a1014-15GeV, the recently discovered X-ray line at 3.5keV in the XMM Newton X-ray observatory data can be explained. We discuss various cosmological aspects of the 7keV axion dark matter such as the production of axion dark matter, the saxion decay process, hot dark matter and isocurvature constraints on the axion dark matter, and the possible baryogenesis scenarios.

Original languageEnglish
Pages (from-to)25-31
Number of pages7
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Publication statusPublished - 2014 Jun 2
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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