Warm dark matter

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Warm dark matter (WDM) is a hypothesized form of

weakly interacting massive particles), when produced non-thermally, could be candidates for warm dark matter. In general, however, the thermally produced WIMPs are cold dark matter
candidates.

keVins and GeVins

One possible WDM candidate particle with a mass of a few

keV comes from introducing two new, zero charge, zero lepton number fermions to the Standard Model of Particle Physics: "keV-mass inert fermions" (keVins) and "GeV-mass inert fermions" (GeVins). keVins are overproduced if they reach thermal equilibrium in the early universe, but in some scenarios the entropy production from the decays of unstable heavier particles may suppress their abundance to the correct value. These particles are considered "inert" because they only have suppressed interactions with the Z boson
.
Sterile neutrinos
with masses of a few keV are possible candidates for keVins. At temperatures below the
Pauli principle
if their mass is larger than 1-8 keV.

In February 2014, different analyses[1][2] have extracted from the spectrum of X-ray emissions observed by XMM-Newton, a monochromatic signal around 3.5 keV. This signal is coming from different galaxy clusters (like Perseus and Centaurus) and several scenarios of warm dark matter can justify such a line. We can cite, for example, a 3.5 keV candidate annihilating into 2 photons,[3] or a 7 keV dark matter particle decaying into a photon and a neutrino.[4]

In November 2019, analysis of the interaction of various galactic halo matter on densities and distribution of stellar streams, coming off the satellites of the Milky Way, they were able to constrain minimums of mass for density perturbations by warm dark matter keVins in the GD-1 and Pal 5 streams. This lower limit on the mass of warm dark matter thermal relics mWDM > 4.6 keV; or adding dwarf satellite counts mWDM > 6.3 keV [5]

See also

  • Dark matter – Hypothetical form of matter that interacts with gravity, but not with light or electromagnetic field
    • Hot dark matter (HDM) – Theoretical form of dark matter particles which travel near the speed of light
    • Cold dark matter (CDM) – Hypothetical type of dark matter in physics
  • Lambda-CDM model – Model of Big Bang cosmology
  • Modified Newtonian dynamics – Hypothesis proposing a modification of Newton's laws

References

  1. ISSN 0004-637X
    .
  2. S2CID 21406370
    .
  3. S2CID 118573978
    .
  4. S2CID 119226364
    .
  5. S2CID 207847306
    .

Further reading


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