Dark Matter Is Born from Ghostly Neutrinos ⚡ экспресс
Sterile neutrinos are a minimal and testable solution to the dark matter problem, but their radiative decay is constrained by X-ray observations. It is shown that cold dark matter from sterile neutrinos is efficiently produced during post-inflation reheating from inflaton decays with a branching ratio BR ≲ 10⁻⁴. This opens up parameter regions where mixing is small, X-ray constraints are avoided, and the observed dark matter density is reproduced. The allowed parameter space is systematically determined: sterile neutrino mass, mixing angle, inflaton mass, reheating temperature, and BR. Sterile neutrinos become a probe of inflationary reheating: future X-ray observations will provide information on the inflaton mass and the ratio m_φ/T_rh. Given a known inflaton mass, this yields a lower bound on the reheating temperature, orders of magnitude stronger than the bound from Big Bang nucleosynthesis.
Visible matter is a drop in the sea of cosmic soup. The foundation of the Universe is made of invisible dark matter, whose gravity keeps galaxies from flying apart. The best candidate for this role is sterile neutrinos, ghost particles connected to us only by the thinnest of bridges.
Immediately after the Big Bang, space suddenly expanded and became extremely hot. A new model shows: if a tiny fraction of that energy went into creating sterile neutrinos, exactly enough were born to explain all dark matter.
The mechanism solves the mystery of the weak signal from neutrinos, bypassing the limitations of telescopes. Now dark matter becomes a tool: future observatories will be able to measure the temperature of that 'cooking,' peering into the first moments after the Big Bang.
🎯 Sterile neutrinos are so elusive that they could fly through a light-year of lead without ever colliding with an atom.