2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/41926The radiatively induced neutrino mass matrix is investigated on the basis of an SU(5) SUSY model. In order to evade the proton decay, an ansatz based on a discrete symmetry $Z_2$ is assumed: although, at the unification scale, we have two types of superfields $Ψ_{L(\pm)}=\bar{5}_{L(\pm)}+10_{L(\pm)}$, which are transformed as $Ψ_{L(\pm)} \to \pm Ψ_{L(\pm)}$ under the discrete symmetry Z$_2$, the particles $Ψ_{L(+)}$ are decoupled after the SU(5) symmetry is broken, so that our quarks and leptons belong to Ψ_{L(-)}. The R-parity-violating terms for our quarks and leptons Ψ_{L(-)} are basically forbidden under the symmetry Z_2. However, we assume that mixings between members of Ψ_{L(+)} and those of Ψ_{L(-)} are in part caused after SU(5) is broken. As a result, the R-parity-violating interactions are in part allowed, so that the neutrino masses are radiatively generated, while the proton decay due to the R-parity violating terms is still forbidden because the term d_R^c d_R^c u_R^c has z=-1.6 pages, Revtex, no figureHigh Energy Physics - Phenomenologytext