Higgs-inflaton mixing and vacuum stability

Abstract

The quartic and trilinear Higgs field couplings to an additional real scalar are renormalizable, gauge and Lorentz invariant. Thus, on general grounds, one expects such couplings between the Higgs and an inflaton in quantum field theory. We find that the often omitted trilinear interaction is only weakly constrained by cosmology and could stabilize the electroweak vacuum by increasing the Higgs selfcoupling. The consequent Higgs–inflaton mixing can be as large as order one making a direct inflaton search possible at the LHC.