Feynman Diagrams For Pedestrians - Herbstschule Maria Laach

6.2 Feynman Rules• vector and axial vector couplingsg V = T 3 − 2Q sin 2 θ wg A = T 3(174a)(174b)• e. g. for electrons• neutral currentsfpfpZ 0fγfg V = − 1 − 4 sin2 θ w2k, µ= − ik, µ, g A = − 1 2g ( )gf2 cos θ V γ µ − g f Aγ µ γ 5w(175)(176)p ′ = − ieQ f γ µ (177)• charged currents (V ff ′ is the CKM matrix)pfk, µW −f ′ = − i √ g V ff ′τ + 1 − γ 5γ µ2 2p ′(178)• triple gauge couplingsk 1 , µ 1W −k Z 02 , µ 2 =W − k 3 , µ 3k 1 , µ 1W − γk 2 , µ 2 =W − k 3 , µ 3ie cot θ w g µ1 µ 2(k 1 µ 3− k 2 µ 3)+ie cot θ w g µ2 µ 3(k 2 µ 1− k 3 µ 1)+ie cot θ w g µ3 µ 1(k 3 µ 2− k 1 µ 2)ieg µ1 µ 2(k 1 µ 3− k 2 µ 3)+ieg µ2 µ 3(k 2 µ 1− k 3 µ 1)+ieg µ3 µ 1(k 3 µ 2− k 1 µ 2)(179)(180)36