  High-energy unitarity is satisfied by adding a sextet quark doublet to QCD.
The sextet sector produces electroweak symmetry breaking and is predicted to
give large cross-section effects at the LHC. It embeds, uniquely, in a massless
SU(5) theory whose bound-state S-Matrix, potentially, reproduces the Standard
Model. Infra-red chirality transitions of the massless Dirac sea play an
essential dynamical role.
