Stable Asymptotically Free Extensions (SAFEs) of the Standard Model

TL;DR

This paper explores extensions of the Standard Model that are asymptotically free with UV fixed points, focusing on models like Pati-Salam that unify couplings and address hierarchy issues.

Contribution

It introduces new asymptotically free Standard Model extensions with UV attractive fixed points, including a Pati-Salam based model with elementary Higgs and potential for low-scale unification.

Findings

Models exhibit couplings flowing to fixed ratios in the UV

Pati-Salam model serves as a minimal example

Hierarchy problem is significantly reduced but not fully resolved

Abstract

We consider possible extensions of the standard model that are not only completely asymptotically free, but are such that the UV fixed point is completely UV attractive. All couplings flow towards a set of fixed ratios in the UV. Motivated by low scale unification, semi-simple gauge groups with elementary scalars in various representations are explored. The simplest model is a version of the Pati-Salam model. The Higgs boson is truly elementary but dynamical symmetry breaking from strong interactions may be needed at the unification scale. A hierarchy problem, much reduced from grand unified theories, is still in need of a solution.