Dias, A. G.Pleitez, VTonasse, M. D.2014-05-202014-05-202004-01-01Physical Review D. College Pk: Amer Physical Soc, v. 69, n. 1, 4 p., 2004.1550-7998http://hdl.handle.net/11449/23140We show that by imposing local Z(13)circle timesZ(3) symmetries in an SU(2)circle timesU(1) electroweak model we can implement an invisible axion in such a way that (i) the Peccei-Quinn symmetry is an automatic symmetry of the classical Lagrangian, and (ii) the axion is protected from semiclassical gravitational effects. In order to be able to implement such a large discrete symmetry, and at the same time allow a general mixing in each charge sector, we introduce right-handed neutrinos and enlarge the scalar sector of the model. The domain wall problem is briefly considered.4engArtigo10.1103/PhysRevD.69.015007WOS:000188785800057Acesso abertoWOS000188785800057.pdf67834333902357270000-0001-5279-8438