A dangerous irrelevant UV-completion of the composite Higgs

TL;DR

This paper proposes a new class of composite Higgs models based on SU(3) gauge theories with light Dirac flavors, offering a viable UV-completion of the Standard Model with distinctive collider signatures like long-lived fractional charge hadrons.

Contribution

It introduces a novel UV-complete composite Higgs framework using SU(3) gauge theories with specific fermion content, addressing Yukawa coupling generation and phenomenological viability.

Findings

SU(3) gauge theories with light Dirac flavors have a strongly-coupled IR fixed point.

Models predict long-lived hadrons with fractional charges as collider signatures.

Exotic scalars gain large positive masses, ensuring custodial symmetry and realistic Higgs phenomenology.

Abstract

One of the most challenging hurdles to the construction of realistic composite Higgs models is the generation of Yukawa couplings for the Standard Model fermions. This problem can be successfully addressed in approximate conformal theories that admit a marginally relevant mixing between composite fermionic operators and the SM fermions. I argue that SU(3) gauge theories with light Dirac flavors in the fundamental representation feature all the ingredients under theoretical control, including a strongly-coupled IR fixed point, composite partners for all Standard Model fermions, absence of Landau poles at low energy, and a realistic phenomenology. These models acquire the status of compelling UV-completions of the SM if some spin-1/2 baryon operator has scaling dimension close to 2.5 within the conformal window, a possibility that can only be assessed via non-perturbative methods like lattice QCD. A distinctive collider signature is long-lived hadrons with fractional charges. Vacuum alignment is controlled by the Nambu-Goldstone bosons of the coset SU(4)xSU(4)/SU(4). With a technically natural choice of mixing for the top-quark, the exotic scalars with electro-weak charges acquire large positive masses and a compelling custodial-symmetric phenomenology is obtained. In the decoupling limit the symmetry breaking pattern effectively reduces to SU(4)->Sp(4) with a light Higgs.