All Questions
11
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Colour Factor in QCD Pair Annihilation
My question occurred when I was reading Introduction to Elementary Particles by David J. Griffiths. In chapter 8, part 8.5, he is calculating the colour factor of quark-antiquark annihilation.
My ...
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47
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What does conservation of color charge mean for mixed states in QCD?
In quantum chromodynamics, in an interaction in which a quark and an anti-quark exchange a gluon, the color charge must be conserved. When we are talking about base states like $r\bar{b}$ it seems ...
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3
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1
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292
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Why $\pi^+$ meson possible combinations of quarks is only three?
I am a starter at nuclear and particles physics. I am reading particles and nuclei an introduction to the physical concepts. There was a paragraph about Colour-neutral particles and how only ...
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1
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91
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How is the colour quantum number not conserved in this process?
I stumbled upon this CERN article, where I found this diagram describing the process $gg \rightarrow HH$:
I'm still new to QCD, and I don't see how a coloured gluon can decay into colourless final ...
2
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1
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183
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Why is the $SU(4)$ group not suitable for describing color symmetry?
How to demonstrate that the $SU(4)$ group cannot be a group of symmetry of a color charge?
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475
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Why don't green and anti-green gluons immediately annihilate each other?
I can't believe I haven't found an answer elsewhere.....
I have read repeatedly about blue/anti-blue gluons, etc., but no reason as to why they don't destroy each other immediately.....
Or maybe they ...
- 4,509
1
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2
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514
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Color symmetries in variant QCD
Suppose we only have two colors, for example, red (R) and blue (B) to construct the wave functions of baryons and mesons and that the color symmetry is SU (2) and not SU (3). In this situation, ...
0
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1
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535
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What exactly is the color charge in QCD? [duplicate]
I don't have strong background in particle physics. Though, I had learnt a little of it. I have gone through the basic of these stuffs (pretty OK).
If I have done my homework right, color charge (R,G,...
user143929
2
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1
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688
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What is the effect of the Gell-Mann matrices on color antiparticles?
I'm studying QCD and I can't understand how exactly are defined the color antiparticles. Indeed, we have the particle color triplet $(r,g,b)$. With the usual SU(3) algebra, we define the 8 Gell-Mann ...
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4
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3
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2k
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How can a detector distinguish between a photon and a gluon
Considering that both gluons and photons have no mass, no charge and spin 1, I was wondering how one can tell the difference, if they hit a detector after a collision at the LHC.
I know that gluons ...
9
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1
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Is there an explanation for the 3:2:1 ratio between the electron, up and down quark electric charges?
I understand that the NNG formula relates $Q$, $I_3$, and $Y$ and can be derived in QCD; does this unambiguously predict the electric charge ratios without making assumptions about the definitions of ...
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