Seesaw Mechanism and Supersymmetry

After almost three decades of intense search for new physics beyond the Standard Model (SM), two ideas stand out to naturally cope with (i) small neutrino masses and (ii) a light higgs boson : Seesaw and SUSY. The combination of these two ideas, i.e. SUSY seesaw exhibits a potentially striking signature: a strong (or even very strong) enhancement of lepton flavour violation (LFV), which on the contrary remains unobservable in the SM seesaw. Indeed, even when supersymmetry breaking is completely flavour blind, Renormalisation Group running effects are expected to generate large lepton flavour violating entries at the weak scale. We explicitly show that in a class of SUSY SO(10) GUTs there exist cases where LFV and CP violation can constitute a major road in simultaneously confirming the ideas of Seesaw and low-energy SUSY.