KISSCaltech
26 minutes
Sterile Neutrino Dark Matter and the Unconfirmed 3.5 keV X-Ray Line
A sterile neutrino decays \( \nu_s \to \nu\gamma \) with \( E_\gamma = m_s c^2 / 2 \), so a 3.5 keV line seen in clusters in 2014 implied m_s ≈ 7 keV; Hitomi and blank-sky searches did not confirm it, and the line remains unconfirmed.