Séminaires : Documents

The impact of non-equilibrium effects on the relic density of dark matter
Maxim Laletin (University of Warsaw)

The standard method of dark-matter (DM) relic-density calculation (which is widely used for the freeze-out mechanism of DM production, but is not limited to it) is based on solving the Boltzmann equation for the number density and relies on the assumption that DM particles are in thermal equilibrium with the SM plasma or a secluded thermal equilibrium in the dark sector is maintained. The interplay of different interactions in some DM models can lead to a deviation of the DM energy distribution from the equilibrium shape before the relic abundance is established and this deviation can have a considerable impact on the predicted amount of DM in the Universe.

In my talk I am going to outline more elaborate approaches to calculating the distribution function of DM particles (and the corresponding DM number density) and consider the application of these methods to two DM scenarios: 1) freeze-in production of DM from semi-annihilation processes; 2) DM models with a strong velocity-dependence of the annihilation rate and the absence of self-interactions.

Finally, I am going to discuss possible connections between non-equilibrium effects and DM phenomenology after the relic density of DM is settled.