Type: Article
Publication Date: 2013-10-29
Citations: 59
DOI: https://doi.org/10.1088/1475-7516/2013/10/057
We investigate the dynamics of the Standard Model higgs with a minimal coupling to gravity during and after inflation. In the regime where the Standard Model vacuum is stable, we find that the higgs becomes a light spectator field after about 30 efolds of inflation, irrespectively of its initial value. Once the higgs has become light, its root-mean-square value h* relaxes to equilibrium in about 85 efolds for the inflationary scale of H* = 104 GeV and in 20 efolds for H* = 1010 GeV. The equilibrium value is given by h* ∼ 0.36λ*−1/4H*, where λ* = 0.09...0.0005 is the higgs self coupling at the scales H* = 104...1010 GeV. We show that the main decay channel of the higgs condensate after inflation is the resonant production of Standard Model gauge bosons. For a set of parameters we find that a significant part of the condensate has decayed in between 340 and 630 Hubble times after the onset of higgs oscillations, depending on H* in a non-trivial way. The higgs perturbations correspond to isocurvature modes during inflation but they could generate significant adiabatic perturbations at a later stage for example through a modulation of the reheating stage. However, this requires that the inflaton(s) decay no later than a few hundred Hubble times after the onset of higgs oscillations.