Higgs inflation still alive

Abstract

The observed value of the Higgs mass indicates that the Higgs potential becomes small and flat at the scale around $10^{17}$GeV. Having this fact in mind, we reconsider the Higgs inflation scenario proposed by Bezrukov and Shaposhnikov. It turns out that the non-minimal coupling $\xi$ of the Higgs-squared to the Ricci scalar can be smaller than ten. For example, $\xi =7$ corresponds to the tensor-to-scalar ratio $r\simeq 0.2$, which is consistent with the recent observation by BICEP2.

Comments: 7 pages, 3 figures; Version to appear on Physical Review Letters, footnotes added and expanded, references added, note added (v2)