2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/196056Supersymmetry offers a cold dark matter candidate, provided that lepton number is {\em not violated by an odd number of units}. On the other hand, lepton number violation by even (two) units gives us an attractive mechanism of neutrino mass generation. Here we offer an explanation of this, in a supergravity framework underlying a supersymmetric scenario, the essential feature being particles carrying lepton numbers, which interact only gravitationally with all other known particles. It is shown that one can have the right amount of $ΔL = 2$ effect giving rise to neutrino masses, whereas the lifetime for $ΔL = 1$ decays of the lightest supersymmetric particle can be prolonged beyond the present age of the universe.8 pages, significant changes in the conceptual ideas and presentation of the paper, minor chages in the title and abstract, added few references. This is to appear in Physical Review DHigh Energy Physics - Phenomenologytext