Hot QCD and warm dark matter

One of the possible explanations for the dark matter needed in the standard cosmological model is so-called warm dark matter, in the form of right-handed (“sterile”) neutrinos with a mass in the keV range. I describe how various properties of QCD at temperatures of a few hundred MeV play an important role in the theoretical computations that are needed for consolidating or falsifying this scenario. In particular the points where lattice QCD could help are underlined.