This seminar discusses models of fermion masses and mixing based on continuous flavour symmetries, emphasizing the phenomenology of the corresponding gauge bosons and — in the global symmetry case — the (pseudo) Nambu-Goldstone bosons arising from spontaneous symmetry breaking. Beginning with a brief overview of the Froggatt-Nielsen U(1) case, I will then focus on a realistic U(2) model. I will show how searches for the light particles associated with these symmetries — especially in flavour-violating decays of leptons and mesons at current and future experiments — can probe exceptionally weak couplings and, consequently, very high energy scales. The talk will also include a brief discussion on the interplay with other probes of high energies, including gravitational wave observatories.
SOM group meeting organisers