Matter-Higgs unification in string-inspired supersymmetric grand unified theories predicts the existence of colored states in the Higgs multiplets and calls for two extra generations of Higgs-like fields ('unhiggses'). If these states are present near the TeV scale, gauge-coupling unification points to the existence of two distinct scales, 10(15) GeV where right-handed neutrinos and a Pati-Salam symmetry appear, and 10(18) GeV where complete unification is achieved. Baryon-number conservation, while not guaranteed, can naturally emerge from an underlying flavor symmetry. Collider signatures and dark-matter physics may be drastically different from the conventional MSSM. (c) 2006 Elsevier B.V. All rights reserved.
展开▼
