The Economical su (3) c su (3) U(1) X Gauge models

The SU(3)C ⊗ SU(2)L ⊗ U(1)Y standard model of strong and electroweak interactions, with the SU(2)L ⊗U(1)Y gauge symmetry spontaneously broken down to the U(1)Q of electromagnetism, is an excellent description of the interactions of elementary particles down to distances in the order of 10−16cm. However, it also leaves many striking features of the physics of our world unexplained. Some of them are the generation number problem, electric charge quantization and neutrino oscillations, which imply that the neutrinos are massive and the flavor lepton number is not conserved. All this requires new interactions beyond the conventional interactions in the standard model.