Electroweak Symmetry Breaking

In the SM, the Higgs boson is a dynamical particle, and there are
loop corrections from its interactions with
◮ the top quark.
◮ the weak gauge bosons,
◮ with itself,
◮ and others.
This results in quantum corrections to the Higgs mass of the order
of
∆mH 2 ∼
m2 t M
(4πv) 2 Λ2 W
2 m
,
(4πv) 2 Λ2 H
2 ,
(4πv) 2 Λ2
where Λ is some cutoff. The top-loop correction violates custodial
symmetry.