Ph. Frampton et Tw. Kephart, CHIRAL ASPON MODEL - AN ALTERNATIVE FULLY GAUGED MODEL OF CP VIOLATION, Physical review. D. Particles and fields, 47(8), 1993, pp. 3655-3657
A chiral aspon model is constructed which avoids problems with quantum
gravity violation of continuous global symmetries. The model contains
only gauged local symmetries before spontaneous symmetry breaking, ha
s no vectorlike fermions with bare mass terms, solves strong CP conser
vation, and has calculable weak CP violation. The model requires axigl
uons with mass locked to the aspon scale.