2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/46146The mass problem in particle physics for other fields is discussed. While the problem of the nuclear masses has been resolved within the QCD framework, 3 parameters of the ``Standard Model'' are related to the fermion sector. The origin of the ferion masses remains unresolved. We discuss attempts to explain the observed hierarchical features of the mass spectrum by a symmetry. relating the mass eigenvalues to the flavor mixing angles.13 latex pagesHigh Energy Physics - Phenomenologytext