Abstract:
We analyze two recent models based on the gauge group SU(3)c×SU(3)L×U(1)N where each generation is not anomaly-free but the anomaly cancels when three generations are taken into account. We show that the most general Yukawa couplings of these models admit a Peccei-Quinn symmetry. This symmetry can be extended to the entire Lagrangian by using extra fields in a very elegant way so that the resulting axion can be made invisible.
