Momentum distributions of cosmic relics: Improved analysis

Understand

We solve coupled momentum-dependent Boltzmann equations for the phase space distribution of cosmic relic particles, without resorting to approximations of assuming kinetic equilibrium or neglecting backscattering or elastic interactions.

• Our method is amendable to precision numerical computations.
• To test it, we consider two benchmark models where the momentum dependence of dark matter distribution function is potentially important: a real singlet scalar extension near the Higgs resonance and a sterile neutrino dark matter model with a singlet scalar mediator.
• The singlet scalar example shows that the kinetic equilibrium may hold surprisingly well even near sharp resonances.