There is a relatively new paper https://arxiv.org/abs/1805.12028 of MiniBooNE on measurements of neutrino oscillations that can only be explained by the postulate of a sterile neutrino. I also read that results from other experiments like IceCube that don't confirm the findings.

Nevertheless I wonder if such a sterile neutrino could not be a good candidate for dark matter. However, on wikipedia: https://en.wikipedia.org/wiki/MiniBooNE it is said that cosmological data give a lower bound of a sterile neutrino to 0.26eV. Is there any possibility that such a particle could turn out as a dark matter candidate ? It was noted that the cosmological bound of the sterile neutrino mass would be quite model-dependent. Which are the models that are responsible for the low cosmological bound of the sterile neutrino mass ?


One has to clearly distinguish sterile neutrinos and their relevance to different areas of research like cosmology or oscillation experiments on earth by their masses. If you want a sterile neutrino to explain the anomalies in oscillation experiments, it should have a mass in the eV range or slightly below, which is the kind of sterile neutrino you are referring too in your question.

If you however want a sterile neutrino to be a dark matter candidate, it has turned out that you need at least a ~keV mass in order to avoid the so-called Tremaine-Gunn bound. It basically tells you that you cannot fit a fermionic dark matter candidate into some galaxies (like dwarf galaxies) at arbitrarily high densities due to Pauli blocking. There exist also many model-dependent mass bounds which might be much more restrictive, such as Lyman-$\alpha$ and Milky Way satellite counts.

I am however not sure how cosmological data give mass bounds to sterile neutrinos that the are subject of these short-baseline experiments like MiniBooNe, i.e. sterile neutrinos with masses in the eV-range. Very interesting though.

  • $\begingroup$ With Tremaine-Gunn bound you mean that there must be a limit on particle density around galaxies due to Pauli-blocking? $\endgroup$ – Frederic Thomas Sep 13 at 11:20
  • $\begingroup$ In principle yes, I think the argument is usually stated in the way that the phase space distribution of fermionic dark matter particles in a galaxy (or in the dark matter halo around it) must not exceed the density of a degenerate Fermi gas in order not to violate the Pauli exclusion principle. $\endgroup$ – Formelverleger Sep 13 at 11:40

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.