  We show that in a spontaneously broken effective gauge field theory,
quantized in a general background $R_\xi$-gauge, also the background fields
undergo a non-linear (albeit background-gauge invariant) field redefinition
induced by radiative corrections. This redefinition proves to be crucial in
order to renormalize the coupling constants of gauge-invariant operators in a
gauge-independent way. The classical background-quantum splitting is also in
general non-linearly deformed (in a non gauge-invariant way) by radiative
corrections. Remarkably, such deformations vanish in the Landau gauge, to all
orders in the loop expansion.

High Energy Physics - Theory;High Energy Physics - Phenomenology