Electroweak Symmetry Breaking

The current-current interaction allows for rewriting it as couplings
of currents to auxiliary vector fields W + µ , W − µ , Z µ :
where
L 6 = −g W (W +µ J + µ + W −µ J − µ ) − g Z (Z µ J 0 µ) + L 2(W ) ,
L 2(W ) = M 2 W W +µ W − µ + 1 2 M2 Z Z µ Z µ .
The vector fields are auxiliary; they can be eliminated by their
equations of motion:
W ± µ
= g W
MW
2 Jµ ∓ ,
Z µ = g Z
MZ
2 Jµ,
0