Generalized Galileons for Particle Physics and Cosmology

TL;DR

This paper reviews recent extensions of Galileon theories, including multi-Galileons from higher co-dimension branes and covariant versions for cosmology, highlighting their theoretical properties and potential applications.

Contribution

It introduces generalized Galileons derived from higher co-dimension branes and covariant formulations, advancing their theoretical framework for particle physics and cosmology.

Findings

Multi-Galileons from co-dimension >1 branes are constructed.

Covariant Galileons suitable for cosmological models are developed.

Generalized Galileons exhibit ghost freedom and non-renormalization properties.

Abstract

In this brief article, I summarize attempts with collaborators over the last couple of years to extend the Galileon idea in two important ways. I discuss the effective field theory construction arising from co-dimension greater than one flat branes embedded in a flat background - the multi-Galileons - and then describe symmetric covariant versions of the Galileons, more suitable for general cosmological applications. These generalized Galileons can be thought of as interesting four-dimensional field theories in their own rights, but the work described here may also make it easier to embed them into higher dimensional theories. I also briefly mention some intriguing properties, including freedom from ghosts and a non-renormalization theorem, that hint at possible applications in particle physics and cosmology