Stabilizing the invisible axion in 3-3-1 models

Abstract

By introducing local [Formula Presented] symmetries with [Formula Presented] in two 3-3-1 models, it is possible to implement an automatic Peccei-Quinn symmetry, keeping the axion protected against gravitational effects at the same time. Both models have a [Formula Presented] domain wall problem and the neutrinos are strictly Dirac particles. © 2004 The American Physical Society.