Higgsflation at the GUT scale in a Higgsless Universe

TL;DR

This paper explores a Higgsless inflation model where a GUT-scale Higgs-like field with non-minimal couplings drives inflation, aligning with observations, while addressing unitarity issues through alternative light degrees of freedom.

Contribution

It introduces a Higgsless inflation scenario with a GUT-scale Higgs-like field controlling gravity and explains how Standard Model unitarity can be maintained without a traditional Higgs.

Findings

Inflation driven by a GUT-scale Higgs-like field with non-minimal couplings.

Standard Model unitarity issues addressed by alternative light degrees of freedom.

Model consistent with cosmological observations.

Abstract

We revisit inflation in induced gravity. Our focus is on models where the low scale Planck mass is completely determined by the breaking of the scaling symmetry in the field theory sector. The Higgs-like field which breaks the symmetry with a GUT-scale vacuum expectation value has non-minimal couplings to the curvature, induced by the gravitational couplings of the other light fields in the theory, so that its expectation value controls the gravitational strength. This field can drive inflation, and give a low energy universe in very good agreement with the cosmological observations. The low energy dynamics of the Standard Model cannot be unitarized by the Higgsflaton, which decouples from the low energy theory, both because it picks up a large mass and because its direct couplings to the low energy modes are weakened. Instead, the short distance behavior of the Standard Model may be regulated by the dynamics of other light degrees of freedom, such as in Higgsless models.