Hidden QCD in Chiral Gauge Theories

TL;DR

This paper introduces a new limit in chiral gauge theories where different Weyl fermions are in distinct representations, revealing a phase where the theory Higgses to ordinary QCD and uncovering a hidden QCD structure for N=3.

Contribution

It proposes a novel limit in chiral gauge theories with mixed fermion representations, showing spontaneous symmetry breaking to QCD and revealing hidden QCD at N=3.

Findings

The theory Higgses to SU(3) QCD via a bilinear condensate.

A phase exists for all N where gauge interactions break to massless QCD.

Hidden QCD is explicitly revealed at N=3.

Abstract

The 't Hooft and Corrigan-Ramond limits of massless one-flavor QCD consider the two Weyl fermions to be respectively in the fundamental representation or the two index antisymmetric representation of the gauge group. We introduce a limit in which one of the two Weyl fermions is in the fundamental representation and the other in the two index antisymmetric representation of a generic SU(N) gauge group. This theory is chiral and to avoid gauge anomalies a more complicated chiral theory is needed. This is the generalized Georgi-Glashow model with one vector like fermion. We show that there is an interesting phase in which the considered chiral gauge theory, for any N, Higgses via a bilinear condensate: The gauge interactions break spontaneously to ordinary massless one-flavor SU(3) QCD. The additional elementary fermionic matter is uncharged under this SU(3) gauge theory. It is also seen that when the number of colors reduce to three it is exactly this hidden QCD which is revealed.