Grand unification and heavy axion

Abstract

We argue that sufficiently complex grand unified theories involving extra strong intractions that confine at very short distances, may lead to a heavy axion solution of the CP problem of QCD. This axion may have a mass within accessible energy range, and its low energy interactions emerge through mixing with axial Higgs boson(s). Another signature of this scenario is softly broken Peccei-Quinn symmetry in the electroweak Higgs sector. We present a toy GUT exhibiting these features.

Comments: A few references added, a typo corrected. 6 pages of LaTeX, no figures