Standard Model with a real singlet scalar and inflation

Kari Enqvist; Sami Nurmi; Tommi Tenkanen; Kimmo Tuominen

doi:10.1088/1475-7516/2014/08/035

paper

Standard Model with a real singlet scalar and inflation

arXiv:1407.0659 · doi:10.1088/1475-7516/2014/08/035

Abstract

We study the post-inflationary dynamics of the Standard Model Higgs and a real singlet scalar $s$ , coupled together through a renormalizable coupling $λ_{s h} h^{2} s^{2}$ , in a $Z_{2}$ symmetric model that may explain the observed dark matter abundance and/or the origin of baryon asymmetry. The initial values for the Higgs and $s$ condensates are given by inflationary fluctuations, and we follow their dissipation and relaxation to the low energy vacua. We find that both the lowest order perturbative and the non-perturbative decays are blocked by thermal effects and large background fields and that the condensates decay by two-loop thermal effects. Assuming instant reheating at $T = 1 0^{16}$ GeV, the characteristic temperature for the Higgs condensate thermalization is found to be $T_{h} \sim 1 0^{14}$ GeV, whereas $s$ thermalizes typically around $T_{s} \sim 1 0^{6}$ GeV. By that time, the amplitude of the singlet is driven very close to the vacuum value by the expansion of the universe, unless the portal coupling takes a value $λ_{s h} ≲ 1 0^{- 7}$ and the singlet $s$ never thermalizes. With these values of the coupling, it is possible to slowly produce a sizeable fraction of the observed dark matter abundance via singlet condensate fragmentation and thermal Higgs scattering. Physics also below the electroweak scale can therefore be affected by the non-vacuum initial conditions generated by inflation.

arXiv comment16 pages, 1 figure, replaced to match published version in JCAP

Standard Model with a real singlet scalar and inflation

Abstract

Cited by in corpus (49)