Feynman rules for electroweak multiplets

1. Oct 11, 2011

Rocky Raccoon

Can someone refer me to Feynman rules for electroweak interactions in the general case of SU(2) multiplets of weak isospin n and weak hypercharge Y interacting with EW gauge bosons?

I can only find the standard rules for SU(2) doublet electron - neutrino.

Thanks!

2. Oct 11, 2011

Bill_K

The interaction term in the standard model Lagrangian is

Lγμ(i∂μ - g/2 τ·Wμ - g'/2 Y Bμ)L + Rγμ(i∂μ - g'/2 Y Bμ)R

where L and R are left- and right-handed fermions and τ are the three Pauli matrices. So all you would have to do for an isospin n fermion is to replace τ by the three SU(2) matrices for isospin n, which are given by

τ±|n m> = √(n∓m)(n±m+1) |n m±1>
τ3|n m> = m |n m>