  Dipole interactions encode a rich variety of phenomena, such as radiative
decays and electric dipole moments in both quark and lepton sectors, which
probe physics beyond the Standard Model up to very high energy scales; due to
renormalization, non-dipole operators mix into dipole ones, thus possibly
generating observable effects that can be investigated by those same phenomena.
I consider four-fermion contact interactions for which the leading order mixing
into dipoles happens at two-loops (i.e., when one-loop effects vanish) and for
which this mixing can avoid small Yukawa couplings, and then explore the
phenomenological consequences for flavour and $ \mathbf{CP} $ violation coming
from New Physics.
