476 Q. Feynman Rules for Tree Graphs in QCD and the Electroweak Theory
Q.2.3 Vertices
Charged current weak interactions
Leptons
−i √ g γ μ
1−
2
γ5
2
Quarks
1−γ5
−i √ g γ μ
2
2 V f f ′
Neutral current weak interactions (no neutrino mixing)
Fermions
where
(
)
−ig
f 1−γ5
f 1+γ5
γ μ c
+ c
,
cos θW
L 2
R 2
c
f
L = t
f
3 − sin
2 θ W Q f
(Q.15)
c
f
R = − sin
2 θ W Q f ,
(Q.16)
and f stands for any fermion.
Vector boson couplings
(i) Trilinear couplings:
γW
+ W
− vertex
Q.2.3 Vertices
Charged current weak interactions
Leptons
−i √ g γ μ
1−
2
γ5
2
Quarks
1−γ5
−i √ g γ μ
2
2 V f f ′
Neutral current weak interactions (no neutrino mixing)
Fermions
where
(
)
−ig
f 1−γ5
f 1+γ5
γ μ c
+ c
,
cos θW
L 2
R 2
c
f
L = t
f
3 − sin
2 θ W Q f
(Q.15)
c
f
R = − sin
2 θ W Q f ,
(Q.16)
and f stands for any fermion.
Vector boson couplings
(i) Trilinear couplings:
γW
+ W
− vertex