Recent content by mkgsec

Hi. I'm having trouble figuring out how SO(N) adjoint rep. transforms under a SO(3) subgroup. Unlike SU(N), SO(N) fundamental N gives \begin{equation} N \otimes N = 1 \oplus A \oplus S \end{equation} So the \begin{equation} S \end{equation} part really bothers. Can you give a help?

It's very clear now! I always assumed that the vacuum is invariant under any operation. Thank you, it was very helpful :)

Well... Maybe because the vacuum contains no particle? Are the invariance of the vacuum and invariance of lagrangian related to each other?

But doesn't Furry's theorem still hold even if the langrangian has no C-symmetry? I thought it is valid as long as the vacuum is invariant under C. What am I missing here?

Hi, I have a question in Srednicki's QFT textbook. In p.460 section 75(about Chiral gauge theory), it says "In spinor electrodynamics, the fact that the vector potential is odd under charge conjugation implies that the sum of these diagrams(exact 3photon vertex at one-loop) must vanish."...