Inflation at the TeV scale with a PNGB curvaton

TL;DR

This paper proposes a novel curvaton mechanism where inflation occurs at a TeV scale, utilizing a PNGB curvaton with an increasing order parameter post-phase transition, compatible with modular inflation models.

Contribution

It introduces a new TeV-scale inflation scenario with a PNGB curvaton that undergoes a phase transition, expanding the range of viable low-scale inflation models.

Findings

Successful realization of TeV-scale inflation with natural parameters

The phase transition must occur well before horizon exit of cosmological scales

The radial mode of the curvaton should be a flaton field

Abstract

We investigate a particular type of curvaton mechanism, under which inflation can occur at Hubble scale of order 1 TeV. The curvaton is a pseudo Nambu-Goldstone boson, whose order parameter increases after a phase transition during inflation, triggered by the gradual decrease of the Hubble scale. The mechanism is studied in the context of modular inflation, where the inflaton is a string axion. We show that the mechanism is successful for natural values of the model parameters, provided the phase transition occurs much earlier than the time when the cosmological scales exit the horizon. Also, it turns our that the radial mode for our curvaton must be a flaton field.