Composite Higgs from Higher Representations

TL;DR

This work proposes dynamical electroweak symmetry breaking from technifermions in two-index representations, placing the theory near the conformal window to suppress FCNC and reduce the $S$ parameter while remaining compatible with precision data. By employing near-conformal (walking) dynamics and orientifold large-$N$ equivalence to SYM, the authors estimate a relatively light composite Higgs mass in the range $m_H \sim 200-500$ GeV for S-type theories, with $N_{T f}=2$ yielding favorable phenomenology. The analysis highlights reduced $S$ via nonperturbative effects and discusses fermion mass generation via ETC, noting the need for non-commuting ETC to reproduce the top mass and the potential role of effective frameworks like little-Higgs. Overall, the models offer a distinct phenomenology from QCD-like technicolor, with viable precision constraints and testable Higgs signatures in a near-conformal, higher-representation context.

Abstract

We investigate new models of dynamical electroweak symmetry breaking resulting from the condensation of fermions in higher representations of the technicolor group. These models lie close to the conformal window, and are free from the flavor-changing neutral current problem despite small numbers of flavors and colors. Their contribution to the S parameter is small and not excluded by precision data. The Higgs itself can be light and narrow.