All Questions
13
questions
2
votes
1
answer
91
views
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
votes
1
answer
183
views
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?
2
votes
2
answers
254
views
Can mesons be in $b \overline{b}$, $r \overline{r}$, $g \overline{g}$ states?
Can a meson be in a pure $b \overline{b}$, $r \overline{r}$, $g \overline{g}$ state or does it have to be in the $\frac{1}{\sqrt{3}}\left(b \overline{b}+r \overline{r}+g \overline{g}\right)$ state?
...
- 631
1
vote
3
answers
2k
views
Why do quarks and gluons have colour?
I asked a question here a few days ago and got some fantastic answers so I'm going to continue.
Let me preface this by saying I know quarks do not actually have 'colour', but colour is some sort of ...
- 311
0
votes
2
answers
333
views
Can the three quark colors be considered to correspond to different particles?
Is it harmless to count three, say, up quark particles instead of one up quark with three colors, as well as 8 different gluons instead of one with different color?
4
votes
1
answer
2k
views
$SU(3)$ Color Symmetry
I have following (maybe a bit general) question about the $SU(3)$-symmetry of color by quarks:
If I consider the analogy to the $SU(2)$-symmetry of isospin $I$ crucially it concers the conservation ...
- 1,395
26
votes
3
answers
5k
views
How (or when) do gluons change the color of a quark?
I know a baryon is only stable when it contains a quark of each color. And as far as I know, the gluon essentially changes the color of a quark and moves onto the next, and this is what holds the ...
- 508
0
votes
1
answer
535
views
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
4
votes
3
answers
916
views
How does quark color affect the identity of a hadron?
I've read about colors relating to quarks and hadrons and I know that they can change colors because of the exchange with gluons, but does changing color change the type of hadron? Does a proton ...
2
votes
1
answer
376
views
Why do we say that gluons carry color charge?
We know that gluons are Lie algebra $su(3)$-valued one-form fiels $A_{\mu}$. And because of $[A_\mu,A_\nu]$ does not vanish generally for the non-Abelian case, gluons have self-interactions. Now how ...
- 3,691
5
votes
1
answer
672
views
Group theoretical reason that Gluons carry color-charge and anti-colorcharge
I was wondering how it is possible to see from the $SU(3)$ Gauge Theory alone that Gluons carry two charges colors: $g\overline{b}$ etc.
Some background:
The W-Bosons (pre-symmetry breaking) form an ...
- 10.1k
9
votes
1
answer
386
views
Are mesons color polarized?
The binding of quarks in mesons baffles me. It's an Occam's Razor thing.
Since a meson is a colorless, the simplest way to bind its two quarks together is to use a $U(1)$ Cartan subalgebra of $SU(3)$. ...
- 22.1k
9
votes
1
answer
2k
views
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 ...
- 7,398