2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/43059Recent experimental data provides evidence for neutrino masses and leads to the possibility of leptonic mixing and CP violation. In this work special attention is dedicated to CP violation in the leptonic sector both at low and at high energies in the framework of seesaw with only three righthanded neutrinos added to the Lagrangean of the Standard Model. It is shown that leptogenesis is a possible and likely explanation for the observed baryon asymmetry of the universe. In this case neutrino masses are constrained yet CP violating phases at low energies can only be related to CP violation at high energies in the context of specific models.Invited talk at 4th International Conference on Physics Beyond the Standard Model: Beyond the Desert (BEYOND 03), Castle Ringberg, Tegernsee, Germany, 9-14 Jun 2003. 10 pages. No figuresHigh Energy Physics - Phenomenologytext