Cosmological Perturbations in the New Higgs Inflation

TL;DR

This work analyzes cosmological perturbations in the New Higgs Inflation scenario where the Higgs kinetic term nonminimally couples to the Einstein tensor. Using the ADM formalism, it derives the scalar and tensor spectra, finding a modified scalar sound speed and a tensor spectrum close to chaotic inflation, with the amplitude governed by the slow-roll parameter ε. The scalar amplitude and spectral index are fitted to WMAP-7 data, yielding ε ≈ 0.0062 and n_S ≈ 0.969, and the authors extract ranges for the Higgs-related scale w and the field value Φ_0, showing the unitarity bound is not violated and about 54 e-folds are obtained. The results demonstrate that inflation driven by the Standard Model Higgs is compatible with current observations, and provide concrete predictions for the fundamental scales of the New Higgs Inflation that can be tested with future data.

Abstract

We study the cosmological perturbations created during the New Higgs inflationary phase. In the New Higgs Inflation, the Higgs boson is kinetically coupled to the Einstein tensor and only three perturbative degrees of freedom, a scalar and two tensorial (gravitational waves), propagate during Inflation. Scalar perturbations are found to match the latest WMAP-7yrs data within Standard Model Higgs parameters. Primordial gravitational waves also, although propagating with superluminal speed, are consistent with present data. Finally, we estimate the values of the parameter of the New Higgs Inflation in relation to the Higgs mass, the spectral index and amplitude of the primordial scalar perturbations showing that the unitarity bound of the theory is not violated.