Hi sir,

I try to calculate the MSSM Wilson coefficients of b->c \tau\nu on the loop level , On the tree level we can type:

Vertex[{bar[Fu], Fd, conj[VWm]}]
Vertex[{bar[Fe], Fv, VWm}]

Any help about what can I use on the loop level ?

Best.

Loop level is, of course, much more complicated. You can use the FlavorKit interface for that: https://arxiv.org/abs/1405.1434