2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/214479In the context of a nonlinear gauge theory of the Poincaré group, we show that covariant derivatives of Dirac fields include a coupling to the translational connections, manifesting itself in the matter action as a universal background mass contribution to fermions.revtex4, 9 pages, no figures, to be published in Eur.Phys.J.C, 2005General Relativity and Quantum CosmologyHigh Energy Physics - TheoryMathematical Physicstext