On thermal production of self-interacting dark matter

Abstract

We consider thermal production mechanisms of self-interacting dark matter in models with gauged Z 3 symmetry. A complex scalar dark matter is stabilized by the Z 3 , that is the remnant of a local dark U(1) d . Light dark matter with large self-interaction can be produced from thermal freeze-out in the presence of SM-annihilation, SIMP and/or forbidden channels. We show that dark photon and/or dark Higgs should be relatively light for unitarity and then assist the thermal freeze-out. We identify the constraints on the parameter space of dark matter self-interaction and mass in cases that one or some of the channels are important in determining the relic density.

Cosmic abundances of SIMP dark matter

“…As a consequence, we find that the required value of κ for the relic density varies by a factor of 3 − 5, depending on n . We note that we kept only the resonant channels in Z n models to show the dependence on the resonance pole but extra non-resonant channels to the same 3 → 2 process can allow for a smaller κ coupling [5,8,9]. Furthermore, other couplings such as λ χ make the model consistent with the bound on the self-scattering cross section of dark matter [5,8,9].…”

A radiative neutrino mass model with SIMP dark matter

“…To accomplish our thought, we refer to the resonant SIMP model constructed in ref. [24] and extend it by introducing more scalars and fermions for neutrino mass generation. Hereafter, we call it νSIMP model.…”

“…Theoretically, the quartic parameters λ j are subject to the conditions of vacuum stability and perturbativity. To ensure the vacuum to be stabilized at large field values, we demand [24] …”

“…In the previous work [24], a condition of perturbativity on the quartic couplings has been taken, which corresponds to λ X,S < 16π in our convention in eq. (2.2).…”

“…For nonzero λ 3 , the numerical results are similar as pointed out in ref. [24]. We have checked our choices of the values of R 1,2 can accommodate the requirements of perturbativity, R 2 1 < λ S < 4π and R 2 2 /9 λ X < 4π with m S 3m X .…”