Relative minus sign?

1. Jun 24, 2011

dimitronic

relative minus sign??

Hi, I have one question for you...
to compute the matrix element for the process u d -> u d I want to use full SM, but I have one problem I'll give you the maths.

process with W:
<ud|(\bar{Ψ}u Ψd)(\bar{Ψ}dΨu)|ud>
process with γ:
<ud|(\bar{Ψ}u Ψu)(\bar{Ψ}dΨd)|ud>
Z and g are the same with γ (i don't write the propagators and the Lorentz parts for simplicity).
Is there a minus sign between W and the others??
I say yes .... but i am not sure.

2. Mar 26, 2017

Deneen2000

I just posted this for another post.... I SAY YES also.
here's the information I found that explains why there is a minus sign.