2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/45591We analyze U(1)$_H$ as a horizontal symmetry and its possibilities to explain the known elementary-fermion masses. We find that only two candidates, in the context of SU(3)$_c\otimes$SU(2)$_L\otimes$U(1)$_Y\otimes$U(1)$_H$ nonsupersymmetric, are able to fit the experimental result m$_b<<$m$_t$.10 pages, Accepted for publication in Z. Phys. CHigh Energy Physics - Phenomenologytext