> By the way, your term "i/2 sigma^uv (p'-p)_v" has an sic: it is either
> "i/2 [gamma^u,gamma^v] (p'-p)_v" or "sigma^uv (p'-p)_v" but not "i/2
> sigma^uv (p'-p)_v."
Actually, Igor, I need to correct the above; your original post was are
correct; I misread the meaning of Weinberg's notation for the sigma^uv.
The calculation I posted at
has a factor that is off by -1/8, that is, all the F_2^2 terms need to
be multiplied by -1/8 to be correct. Corrected repost will follow in