A gravitational wave background from the decay of the standard model Higgs after inflation

The stability of the Standard Model (SM) at high energies implies that the SM Higgs forms a condensate during inflation, which starts oscillating soon after the inflationary stage ends. This causes the Higgs to decay very fast, via non-perturbative effects, into all the SM fields coupled directly to it. The excited species act as a source of gravitational waves (GWs), and as a result, all Yukawa and SU(2)(L) gauge couplings of the SM are imprinted as features in the GW spectrum. In practice, the signal is dominated by the most strongly interacting species, rendering the information on the other species inaccessible. To detect this background new high frequency GW detection technology is required, beyond that of currently planned detectors. If detected, this signal could be used for measuring properties of high-energy particle physics, including beyond the SM scenarios.