GRAND UNIFICATION AND HEAVY AXION

We argue that sufficiently complex grand unified theories involving ex tra strong intractions that confine at very short distances may lead t o a heavy axion solution of the CP problem of QCD. This axion may have a mass within the accessible energy range, and its low-energy interac tions emerge through mixing with axial Higgs boson(s). Another signatu re of this scenario is softly broken Peccei-Quinn symmetry in the elec troweak Higgs sector. We present a toy GUT exhibiting these features. (C) 1997 American Institute of Physics.