Electroweak Symmetry Breaking

Remark on the anomalous couplings:
They cannot be exactly zero; all operators appear as counterterms
to one-loop divergencies of the effective Lagrangian. For a precise
definition, one needs a renormalization scheme.
They cannot be exactly zero; scattering amplitudes of massive
vector bosons are unbounded at high energies and violate the
unitarity limit, hence corrections must be present such that the
unitarity limit is not violated.
This is true only for part of the couplings. If (as experimentally
confirmed),
β ′ ≈ 0, i.e. M W = c w M Z ,
half of the operators (those containing the T factor) do not appear
as one-loop counterterms.