Higgs-portal assisted Higgs inflation with a sizeable tensor-to-scalar ratio

摘要

We show that the Higgs portal interactions involving extra dark Higgs fieldcan save generically the original Higgs inflation of the standard model (SM)from the problem of a deep non-SM vacuum in the SM Higgs potential.Specifically, we show that such interactions disconnect the top quark pole massfrom inflationary observables and allow multi-dimensional parameter space tosave the Higgs inflation, thanks to the additional parameters (the dark Higgsboson mass $m_{\phi}$, the mixing angle $\alpha$ between the SM Higgs $H$ anddark Higgs $\Phi$, and the mixed quartic coupling) affecting RG-running of theHiggs quartic coupling. The effect of Higgs portal interactions may lead to alarger tensor-to-scalar ratio, $0.08 \lesssim r \lesssim 0.1$, by adjustingrelevant parameters in wide ranges of $\alpha$ and $m_{\phi}$, some region ofwhich can be probed at future colliders. Performing a numerical analysis wefind an allowed region of parameters, matching the latest Planck data.