If the weak were strong and the strong were weak

Abstract

We explore the phase structure of the Standard Model as the relative strengths of the SU(2)SU(2) weak force and SU(3)SU(3) strong force are varied. With a single generation of fermions, the structure of chiral symmetry breaking suggests that there is no phase transition as we interpolate between the SU(3)SU(3)-confining phase and the SU(2)SU(2)-confining phase. Remarkably, the massless left-handed neutrino, familiar in our world, morphs smoothly into a massless right-handed down-quark. With multiple generations, a similar metamorphosis occurs, but now proceeding via a phase transition. In the second half of the paper we introduce a two-parameter extension of the Standard Model, a chiral gauge theory with gauge group U(1)\times Sp(r)\times SU(N)U(1)×Sp(r)×SU(N). We again explore the phase structure of the theory as the relative strengths of the Sp(r)Sp(r) and SU(N)SU(N) gauge couplings vary.