Higgs inflation using the unstable standard model potential

It is likely that the Higgs potential of the Standard Model is unstable, turning negative at phi < Lambda similar to 10(10) GeV. Here we consider whether it is possible to have Higgs inflation on the positive stable region of the potential at phi < Lambda. To do this we add a nonminimally coupled induced gravity sector with scalar chi to the Standard Model. For an appropriate form for the nonminimal coupling of chi, we show that it is possible to have conventional Higgs inflation at small phi < Lambda if the effective Planck mass in the Jordan frame during inflation is sufficiently small, with a phase transition to chi not equal 0 at the end of Higgs inflation which increases the Jordan frame Planck mass to its presently observed value. In the Einstein frame this corresponds to a suppression of the Higgs kinetic and potential term at the end of inflation. We show that the predictions of Higgs inflation at tree level are unaltered from conventional Higgs inflation, with the exception of the magnitude of the Higgs field during inflation. Hence, Higgs inflation can be achieved using the potential of the unmodified Standard Model.

Automated summary

In this paper, we explore the possibility of Higgs inflation in the positive stable region of the potential by introducing a nonminimally coupled induced gravity sector to the Standard Model. We show that under certain conditions, conventional Higgs inflation can be achieved by increasing the effective Planck mass during inflation through a phase transition of another scalar field chi.