Sterile neutrino Dark Matter production from scalar decay in a thermal bath

Abstract

Abstract:We calculate the production rate of singlet fermions from the decay of neutral or charged scalar fields in a hot plasma. We find that there are considerable thermal corrections when the temperature of the plasma exceeds the mass of the decaying scalar. We give analytic expressions for the temperature-corrected production rates in the regime where the decay products are relativistic. We also study the regime of non-relativistic decay products numerically. Our results can be used to determine the abundance and momentum distribution of Dark Matter particles produced in scalar decays. The inclusion of thermal corrections helps to improve predictions for the free streaming of the Dark Matter particles, which is crucial to test the compatibility of a given model with cosmic structure formation. With some modifications, our results may be generalised to the production of other Dark Matter candidates in scalar decays.

A White Paper on keV sterile neutrino Dark Matter

“…These affect both, the equation of motion for the scalar condensate [737] as well as the properties and kinematics of quasiparticles in the plasma [738,739]. Moreover, the gauge interactions open up additional channels for DM production in 2 → 2 scatterings in addition to the decay [685].…”

“…In general, if the amount of thermal degrees of freedom g * changed during the production process, an explicit solution of the Boltzman equations is required [730]. Another subtlety appears at early times, when the temperature of the plasma exceeds mass of the decaying particle [685]. This case is mostly relevant if the decay width of the scalar is very large, so that the scalar should be considered as an intermediate state.…”

Variations on the vev flip-flop: instantaneous freeze-out and decaying dark matter

“…These finite-temperature effects are known to cause important phenomena in the development of the universe, such as the electroweak phase transition (EWPT). Recently there has been interest in understanding the impact of finite temperature effects in mechanisms of DM production [8][9][10][11][12][13][14][15][16][17].…”

Right-handed neutrino dark matter under the B − L gauge interaction

“…As another way out, introducing extra interactions can provide a viable dark matter production mechanism that is independent of the mixing angle θ 1 . For instance, the N 1 can be produced by the decay of a scalar particle [18][19][20][21][22][23][24][25][26][27][28] through the freeze-in mechanism [29,30]. (For a discussion on the freeze-in scenario for the hidden sector dark matter that communicates with our sector through the kinetic mixing and/or the scalar mixing, see refs.…”