All Questions
Tagged with quantum-chromodynamics representation-theory
7
questions with no upvoted or accepted answers
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134
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What is the physical meaning of Lie congruence classes?
Any weight $\lambda$ characterising a representation of $\mathfrak{su}(N)$ is an element of one of the $N$ congruence classes defined by (ref.1)
$$
\lambda_1+2\lambda_2+\cdots+(N-1)\lambda_{N-1}\quad\...
3
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0
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297
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Formal definition of gauge field and spinors in QFT
I am trying to pin down what spaces a spinor and gluon gauge field exactly occupy. I know that the spinor is a quantity $\psi_{i\alpha f}(\vec x, t)$ where
$i$ is a color index in the fundamental ...
- 8,439
1
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195
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Why does the $U(2n)$ flavor symmetry break down to a $U(1)$ group and an $SU(2n)$ group?
I am studying quantum field theory using Srednicki's textbook. Problem 83.1 is:
Suppose that the color group is $G_C=SO(3)$ rather than $SU(3)$, and that each quark flavor is represented by a Dirac ...
- 1,653
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683
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SU(3) adjoint representation's invariant tensors
Considering a complex scalar field $\varphi^a$ that transform in the adjoint representation (8) of SU(3).
A quartic interaction term SU(3) invariant is
$$\lambda C^{abcd}\varphi^{\dagger a} \varphi^...
- 21
1
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0
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280
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Names for various color indices in QCD
In Quantum Chromodynamics with $\mathrm{SU}(3)$ there are at least two types of color indices:
Indices $a$, $b$, … that index the eight generators of the group $\mathrm{SU}(3)$. In some sense they ...
- 8,439
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244
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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 $$...
user242231
0
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What is the application of dimension $6$ representation of $SU(3)$ in particle physics?
As we know, the $uds$ transforms in fundamental representations of $SU(3)$. It has the antifundamental partner. According to representation theory,
$$
\mathbf{3} \otimes \mathbf{\bar{3}}= \mathbf{8} \...
