The Minimal Moose for a Little Higgs
N. Arkani-Hamed, A. G. Cohen, T. Gregoire, E. Katz, A. E. Nelson, J. G. Wacker
TL;DR
This work presents a minimal little-Higgs model, the Minimal Moose, where the Higgs arises as a pseudo-Goldstone boson and 1-loop quadratic divergences are canceled by new TeV-scale partners of the same statistics, avoiding the need for supersymmetry. The two-site, four-link theory-space construction employs a moose diagram with gauge groups $G_1=SU(3)$ and $G_2=SU(2)\times U(1)$ connected by four link fields, yielding a SM-like low-energy spectrum with two light Higgs doublets plus a triplet and a singlet, while heavy states live at $\sim$ TeV. The top Yukawa sector plays a central role by generating the entire Higgs potential and, in a companion variant, can drive EWSB entirely through top-sector dynamics with natural quartic couplings. The approach achieves natural EWSB up to a cutoff $\Lambda \sim 10$ TeV, maintains consistency with precision electroweak constraints, and offers a predictive, economical alternative to low-energy SUSY with a restrained new-particle content and clear paths to UV completions.
Abstract
Recently a new class of theories of electroweak symmetry breaking have been constructed. These models, based on deconstruction and the physics of theory space, provide the first alternative to weak-scale supersymmetry with naturally light Higgs fields and perturbative new physics at the TeV scale. The Higgs is light because it is a pseudo-Goldstone boson, and the quadratically divergent contributions to the Higgs mass are cancelled by new TeV scale ``partners'' of the {\em same} statistics. In this paper we present the minimal theory space model of electroweak symmetry breaking, with two sites and four link fields, and the minimal set of fermions. There are very few parameters and degrees of freedom beyond the Standard Model. Below a TeV, we have the Standard Model with two light Higgs doublets, and an additional complex scalar weak triplet and singlet. At the TeV scale, the new particles that cancel the 1-loop quadratic divergences in the Higgs mass are revealed. The entire Higgs potential needed for electroweak symmetry breaking--the quartic couplings as well as the familiar negative mass squared--can be generated by the top Yukawa coupling, providing a novel link between the physics of flavor and electroweak symmetry breaking.