All Questions
29
questions
9
votes
3
answers
2k
views
Why are gluons massless as their range is finite?
The range of electromagnetic waves and gravitational force is infinity and the particles exchanged during these interactions are photons and gravitons respectively. Both are massless following the ...
3
votes
1
answer
530
views
Why do gluon jets have more particles?
From papers on the concept of quark/gluon jet tagging, I've seen that gluon jets have more particles and a broader radiation pattern. Why does carrying more color charge allow them to produce more ...
- 979
3
votes
1
answer
213
views
What gives rise to mass gap for gluons, even if they are massless?
It is known that QED does not have a mass gap.
On the other hand, at the heuristic level, QCD has a mass gap.
But photons and gluons are both "massless". Could anyone explain (at least at ...
- 1,669
0
votes
1
answer
100
views
Is there an energy release from gluon expansion and contraction?
When an electron drops to a lower orbit, energy is released as a photon. Gluons expand and contract in-between quarks, described like springs or rubber bands that have tremendous force when extended ...
- 4,783
0
votes
1
answer
83
views
Are glueballs confined without a connection to quarks?
Without being bound to quarks through the strong force, is there any reason why glue balls would be confined? Are they confined
- 4,783
5
votes
4
answers
667
views
Why are gluons color charged but not photon? Could there be a charged EM force carriers like gluons or neutral color charge carrier like photon?
Gluons have a color charge why don't photons have an electric charge like gluons?
0
votes
1
answer
129
views
Can a gluon split into three gluons: $g \rightarrow ggg$? (four gluon vertex)
I know $gg \rightarrow gg$ is possible, but is $g \rightarrow ggg$ possible? I don't see this anywhere although I think you could conserve colour charge (e.g. $r\bar{g} \rightarrow r\bar{g} + g\bar{b}...
- 351
0
votes
1
answer
185
views
Is $SU(3)$ (and not $U(3)$) the symmetry group of color interactions because $U(1)$ is already used for EM?
I have already seen this question. It was answered that $U(3)$ can be decomposed into $SU(3) \times U(1)$, and $U(1)$ is already used for the EM interaction. Still, I wonder why the EM interaction ...
7
votes
1
answer
976
views
Do gluons care about flavor?
I think the answer to my question is no, but I can't find an explicit statement about this on my books or online.
I know that gluons are the vector bosons for QCD, the $SU(3)$ gauge theory of color, ...
- 5,931
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 ...
1
vote
0
answers
63
views
Can the process gluon + gluon $\rightarrow$ 2 Higgs proceed in the following way in the standard model?
At order $g_s^2$, usually only a triangle quark loop and box diagram are considered, I was wondering, is there some reason that excludes these diagrams from the possible standard model channels?
6
votes
1
answer
577
views
How do we know that gluons have no electric charge?
Since the W boson carries electric charge and there is no a priori reason that massless electrically charged bosons cannot exist, I'm wondering if the lack of gluon electric charge has been confirmed ...
- 113
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
1
answer
350
views
Comparison between $\rho^0$ and $J/\psi$ decay mode
Why must a hadronic decay of the $J/\psi$ meson include (at least) three gluons? Why is the decay mediated by a single gluon allowed for the $\rho^0$ meson?
5
votes
3
answers
3k
views
Do gluons decay?
I have seen examples of other particles that decay into gluons but do gluons themselves ever decay. Since gluons are not composed of anything else I assume they are fundamental.
On there other hand ...
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