Dias, Alex G.Pleitez, V. [UNESP]2022-04-282022-04-282004-01-01Physical Review D - Particles, Fields, Gravitation and Cosmology, v. 69, n. 7, p. 4-, 2004.1550-23681550-7998http://hdl.handle.net/11449/224590By 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.4engArtigo10.1103/PhysRevD.69.0777022-s2.0-2442653093