$SU(5)_{L} \times U(1)_{Y}$ electroweak unification

Abstract

We propose here -for the first time in the literature, to our best knowledge -an electroweak unification based on the SU (5) L × U (1) Y gauge group. The spontaneous symmetry breaking takes place in the manner SU (5) L × U (1) Y → U (1) em , due to a particular Higgs sector consisting of five scalar quintuplets. Each scalar quintuplet acquires its own vacuum expectation value, by means of a proper parametrization which is worked out once the overall vacuum expectation value in the model is established. The decoupling of the low energy regime (corresponding to the Standard Model) from the high scale (required by out model here) is straightforwardly achieved in order to preserve the consistency with the present experimental data. Finally, a promising phenomenological outcome is derived by simply tuning a single free parameter. Our results include, besides a viable one-parameter mass spectrum, also the prediction of precisely three generations in the fermion sector and the electric charge quantization.

Challenges for the 3-3-1 models

“…Similar features occurs in model with the gauge symmetries SU (3) C ⊗ SU (4) L ⊗ U (1) N [152][153][154][155], or in models with SU (3) C ⊗ SU (5) L ⊗ U (1) N [41,156,157]. In fact, if right-handed neutrino do really exist in nature the more interesting model will be those with 3-4-1 symmetry [152] in which the known leptons and the right-handed neutrinos are in the fundamental representation of SU (4).…”