avor violation. Our setting is a prime example of how high- and low-energy physics can cross-fertilize each other. The origin of neutrino mass and mixing is an outstanding open question, as the existence of massive neutrinos, which follows from the discovery of neutrino oscillations [1, 2], cannot be accommodated within the Standard Model (SM) of particle physics. Together with other puzzles like the nature of Dark Matter or the generation of the observed matter-antimatter asymmetry in the Universe, this constitutes a leading motivation to search for new physics beyond the SM. The experimental eort to unravel the nature and properties of such new physics is pursued along three main avenues: the energy, intensity, and cosmic frontiers, which provide highly complementary probes of new physics. A prime example of such a complementarity arises if the new physics responsible for neutrino masses and mixings lies not very far above the electroweak scale, case in which both low and high-energy experiments could be sensitive to it. However, even though there are well-motivated scenarios for the generation of neutrino masses and mixings which predict signatures at both the intensity and high-energy frontiers, such as low-scale seesaw models (see e.g. the discussion in [3]) and loopinduced models [4{9], these scenarios generically predict the existence of multiple new particles, making concrete predictions for phenomenology dicult