New Directions for New Dimensions: From Strings to Neutrinos to Axions to...
In this talk, I discuss recent developments concerning the possibility of large extra spacetime dimensions. After briefly reviewing how such dimensions can lower the fundamental GUT, Planck, and string scales, I then outline how these scenarios lead to a new higher-dimensional seesaw mechanism for generating neutrino oscillations --- perhaps even without neutrino masses. I also discuss how extra dimensions lead to new mechanisms contributing to the “invisibility” of the QCD axion. This talk reports on work done in collaboration with Emilian Dudas and Tony Gherghetta.