Standard Model with a real singlet scalar and inflation

• Published in: Journal of cosmology and astroparticle physics 2014-08, Vol.2014 (8), p.35-35
• Main Authors: Enqvist, Kari, Nurmi, Sami, Tenkanen, Tommi, Tuominen, Kimmo
• Format: Article
• Language: English
• Subjects: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BARYONS; COSMOLOGICAL INFLATION; COUPLING; EXPANSION; FLUCTUATIONS; HIGGS MODEL; NONLUMINOUS MATTER; RENORMALIZATION; SCATTERING; STANDARD MODEL; SYMMETRY; UNIVERSE
• ISSN: 1475-7516; 1475-7516
• DOI: 10.1088/1475-7516/2014/08/035

We study the post-inflationary dynamics of the Standard Model Higgs and a real singlet scalar s, coupled together through a renormalizable coupling λ{sub sh}h{sup 2}s{sup 2}, in a Z{sub 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=10{sup 16} GeV, the characteristic temperature for the Higgs condensate thermalization is found to be T{sub h} ∼ 10{sup 14} GeV, whereas s thermalizes typically around T{sub s} ∼ 10{sup 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{sub sh}∼