Natural Top-Bottom Mass Hierarchy in Composite Higgs Models

Abstract

We consider composite two-Higgs doublet models based on gauge-Yukawa theories with strongly interacting fermions generating the top-bottom mass hierarchy. The model features a single "universal" Higgs-Yukawa coupling, $g$, which is identified with the top quark $g\equiv g_t\sim \mathcal{O}(1)$. The top-bottom mass hierarchy arises by soft breaking of a ${\mathbb{Z}}_2$ symmetry by a condensate of strongly interacting fermions. A mass splitting between vector-like masses of the confined techni-fermions controls this top-bottom mass hierarchy. This mechanism can be present in a variety of models based on vacuum misalignment. For concreteness, we demonstrate it in a composite two-Higgs scheme.

Comments: 6 pages, 1 figure, 2 tables