The survival principle is modified in a manner suggested by unified theories, which generally leave relic discrete symmetries, in addition to the SU(3) × SU(2) × U(1) gauge symmetry, unbroken down to low (≤104 GeV) energies. Suitable discrete "mirror symmetries" of this type will make the existence of mirror fermions, required by several attractive theoretical speculations, consistent with phenomenology. We discuss phenomenological consequences of such schemes, paying special attention to the importance of apparent non-renormalizable interactions in the low energy effective theory. Unified theories based on SO(16) and SO(18) gauge groups provide examples; the latter appears particularly attractive.
ASJC Scopus subject areas
- Nuclear and High Energy Physics