Why is parity maximally violated in weak interactions?

[touqra]

Why do they always say parity is maximally violated in weak interaction? This is true for W boson interactions. But not for Z bosons, as the Zs couple to both left and right handed particles. And hence, is not maximally violated in the case of Z.

 

[Vanadium 50]

Electroweak symmetry is broken; this is one symptom. The unbroken symmetry contains a w1, w2 and w3 that couple to left-handed fermions and a B0 that couples to both handednesses. When the symmetry breaks, the w1 and w2 become the massive W+ and W-, but the w3 and B0 mix to produce a photon which couples to both, and a Z0 which couples purely left-handedly to neutral particles, and progressively more right-handedly to particles with more charge.

 

[pam]

Why do they always say parity is maximally violated in weak interaction? This is true for W boson interactions. But not for Z bosons, as the Zs couple to both left and right handed particles. And hence, is not maximally violated in the case of Z.

The term "maxilmally violated" arose 50 years ago because the charged current weak interactions, which were the only ones seen for a long time, had equal parts of V and A.