COMPOSITE AXION MODELS AND PLANCK SCALE PHYSICS

Recently it has been argued that global symmetry violating effects at the Planck scale could upset axion based solutions to the strong CP problem if there is no gauge symmetry to prevent the generation of global symmetry violating operators. We show that it is straightforward to construct composite axion models for which global symmetry violating effects are very suppressed. The PQ symmetry of these models can be legitimately regarded as an approximate accidental symmetry. Similar considerations apply to the texture scenario, although models are more constrained.