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0 votes
0 answers
244 views

One-loop renormalization of the gauge coupling

Quoting Yuji Tachikawa, chapter 3 of "${\cal N}=2$ Supersymmetric Dynamics for Pedestrians": Recall the one-loop renormalization of the gauge coupling in a general Lagrangian field theory $$...
user avatar
4 votes
3 answers
1k views

Is the concept of bicolored gluons mathematically precise/meaningful? Please explain

Each flavour of quark carries a colour quantum number: red, green or blue. I know what it means mathematically. But elementary textbooks (e.g, particle physics by Griffiths) also say that gluons are ...
Solidification's user avatar
12 votes
1 answer
1k views

How many colors really are there in QCD?

In abelian gauge theory (electrodynamics), the matter fields transform like (please correct me if I am wrong) $$ |\psi\rangle\rightarrow e^{in\theta(x)}|\psi\rangle\tag{1} $$ under a gauge ...
user306604's user avatar
2 votes
2 answers
288 views

Do the “$SU(3)$ colors” live in a 3-dimensional vector space?

Previously I asked a question about the visualized colors: Do the "colors" live in a 3-dimensional vector space? (My earlier question is unfortunately closed) Now I like to ask the “$SU(3)$ ...
ann marie cœur's user avatar
1 vote
1 answer
630 views

"Color charge" of the adjoint fermion?

What kind of "color charge" does the adjoint fermion carry? Let us consider the SU(N) gauge theory. The gauge field is in the adjoint representation (rep). Well-Konwn: If the fermion is in SU(N) ...
ann marie cœur's user avatar