Reheating and Dark Matter Freeze-in in the Higgs-$R^2$ Inflation Model

Abstract

We study the post-inflationary dynamics for reheating and freeze-in dark matter in the Higgs-R 2 inflation model. Taking the perturbative approach for reheating, we determine the evolution of the temperature for radiation bath produced during inflation and determine the maximum and reheating temperatures of the Universe. Adopting a singlet scalar dark matter with a conformal non-minimal coupling and a vanishing Higgs-portal coupling, we discuss the freeze-in production of dark matter both from the non-thermal scattering during reheating and the thermal scattering after reheating. We find that the non-thermal inflaton scattering process is dominant for dark matter production in most of the parameter space. The reheating temperature in our model is determined dominantly by the Higgs condensate to be up to about 10 14 GeV and dark matter with masses up to about 10 5 GeV can be produced with a correct relic density.

Dissipation of oscillating scalar backgrounds in an FLRW universe

“…The second class is characterized by a non-vanishing imaginary part of the retarded four-vertex function, the σ defined in Eq. (34), and contains the processes given in Eq. (53).…”

“…Perturbative particle production is usually studied by the time-dependent perturbation theory, see, e.g., Ref. [33,34]. These methods typically assume a fixed classical background and the computation is usually done at zero temperature, thus missing the backreaction effects and thermal effects.…”

Fate of oscillating homogeneous ℤ2-symmetric scalar condensates in the early Universe

“…The coupled EoMs derived in this work could be used for investigating perturbative production of DM from an oscillating scalar field [45] and perturbative reheating [46][47][48][49]. However, it is important to note that our derivation assumes all particles in the plasma are in thermal equilibrium.…”

Effects of gravitational particle production on Higgs portal dark matter

“…For such a case the gravitational effect is negligible and we do not consider this scenario. For very small coupling λ, on the other hand, DM is never thermalized but still produced gradually through the Higgs portal coupling and it can account for the observed DM abundance [31][32][33]. In this paper we fully include the effect of Higgs portal coupling and the gravitational coupling for the scalar DM production mechanisms and evaluate the DM abundance.…”