A Composite Little Higgs Model

TL;DR

This work constructs a natural, UV-complete realization of a composite little Higgs where the Higgs is a $p$NGB of the $SU(5)/SO(5)$ coset with a softly broken shift symmetry. Below the TeV scale the effective theory reproduces the SM with a light Higgs and an extra neutral scalar, while at the TeV scale a set of scalars, gauge bosons, and vector-like $Q=2/3$ quarks cancel the one-loop quadratic divergences, aided by a top-sector dynamics that drives electroweak symmetry breaking. The UV completion employs a softly broken SUSY theory at $\,\sim10$ TeV that becomes strongly coupled and confines, producing composite fermions and a natural top Yukawa, along with a discrete dark matter parity that yields a stable LPOP. The model also provides a general EFT framework for precision electroweak corrections and flavor, yielding viable phenomenology with a potentially observable dark matter candidate and TeV-scale partners at colliders. Its landscape offers a clear, technically natural alternative to the MSSM with distinctive experimental signatures at the LHC.

Abstract

We describe a natural UV complete theory with a composite little Higgs. Below a TeV we have the minimal Standard Model with a light Higgs, and an extra neutral scalar. At the TeV scale there are additional scalars, gauge bosons, and vector-like charge 2/3 quarks, whose couplings to the Higgs greatly reduce the UV sensitivity of the Higgs potential. Stabilization of the Higgs mass squared parameter, without finetuning, occurs due to a softly broken shift symmetry--the Higgs is a pseudo Nambu-Goldstone boson. Above the 10 TeV scale the theory has new strongly coupled interactions. A perturbatively renormalizable UV completion, with softly broken supersymmetry at 10 TeV is explicitly worked out. Our theory contains new particles which are odd under an exact "dark matter parity", (-1)^{(2S+3B+L)}. We argue that such a parity is likely to be a feature of many theories of new TeV scale physics. The lightest parity odd particle, or "LPOP", is most likely a neutral fermion, and may make a good dark matter candidate, with similar experimental signatures to the neutralino of the MSSM. We give a general effective field theory analysis of the calculation of corrections to precision electroweak observables.