Abstract
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 ma≃7 keV and the decay constant fa≃1014–15 GeV, the recently discovered X-ray line at 3.5 keV in the XMM Newton X-ray observatory data can be explained. We discuss various cosmological aspects of the 7 keV 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.
Highlights
In supergravity and superstring theories there appear many moduli fields at low energy scale through compactifications of extra dimensions [1]
In this letter we propose a scenario in which the 7 keV axion dark matter decaying into photons explains the origin of the 3.5 keV X-ray line, while the saxion dominates the Universe and reheats the standard model (SM) sector via the same dilatonic coupling in SUSY
We have focused on a modulus field which is stabilized by the SUSY breaking effect and its axion component remains much lighter than the saxion component
Summary
In supergravity and superstring theories there appear many moduli fields at low energy scale through compactifications of extra dimensions [1]. In this letter we propose a scenario in which the 7 keV axion dark matter decaying into photons explains the origin of the 3.5 keV X-ray line, while the saxion dominates the Universe and reheats the SM sector via the same dilatonic coupling in SUSY. One of the main differences is the SUSY breaking scale, i.e., the gravitino mass They focused on the light gravitino mass between keV and MeV, and consider moduli dark matter with a similar mass, which corresponds to the real component of the moduli, i.e. the saxion, in our scenario. We can unambiguously discuss the saxion and axion cosmology
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
