Flavon Inflation

TL;DR

This paper introduces a novel class of inflation models where flavon fields, responsible for family symmetry breaking in particle physics, serve as inflatons, linking cosmology with flavor physics and avoiding GUT-related monopole problems.

Contribution

It proposes flavon fields as inflaton candidates in new and hybrid inflation models, connecting inflationary dynamics with flavor symmetry breaking.

Findings

Flavon fields can naturally drive inflation without monopole issues.

Models based on discrete and continuous family symmetries are viable for inflation.

Inflation scale is below GUT scale, avoiding related topological problems.

Abstract

We propose an entirely new class of particle physics models of inflation based on the phase transition associated with the spontaneous breaking of family symmetry responsible for the generation of the effective quark and lepton Yukawa couplings. We show that the Higgs fields responsible for the breaking of family symmetry, called flavons, are natural candidates for the inflaton field in new inflation, or the waterfall fields in hybrid inflation. This opens up a rich vein of possibilities for inflation, all linked to the physics of flavour, with interesting cosmological and phenomenological implications. Out of these, we discuss two examples which realise flavon inflation: a model of new inflation based on the discrete non-Abelian family symmetry group A_{4} or Delta_{27}, and a model of hybrid inflation embedded in an existing flavour model with a continuous SU(3) family symmetry. With the inflation scale and family symmetry breaking scale below the Grand Unification Theory (GUT) scale, these classes of models are free of the monopole (and similar) problems which are often associated with the GUT phase transition.