All Questions
13
questions
0
votes
0
answers
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 ...
- 1
0
votes
1
answer
90
views
How do scientists attempt to break quark confinement?
From what I understand, when energy is supplied to quarks, it elongates the gluon tube and when enough energy is put in, new quarks are formed, keeping quark confinement. However, I am inquisitive ...
- 625
-3
votes
1
answer
209
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Do Quarks Exist?
Do Quarks Really Exist?
Is there any experiment which can confirm the existence of Quarks and what kind of force is that which binds them to form neutron and proton?
- 31
14
votes
5
answers
2k
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Why aren't all quarks clumped together in one giant hadron?
As far as I am aware, the strong interaction is attractive only, and its carrier, the gluon, is massless meaning it has unlimited range. If this is the case, how come we only observe quarks in pairs ...
- 451
2
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0
answers
783
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QCD energy scale $\Lambda_{\rm MS} $, $\Lambda_{\rm QCD}$, ...?
Why there seems to be different conventions of QCD energy scales? Is that due to the running coupling?
For example in Wikipedia https://en.wikipedia.org/wiki/Coupling_constant#QCD_scale:
$$
\Lambda_{\...
- 4,336
4
votes
3
answers
272
views
Why quarks are confined? Why can't they be found in unbound states?
No one has observed before a "free" quark, i.e. a quark in an unbound state. According to one paper, I read that $p\bar{p}$ collision produce unbound $t\bar{t}$ pair which quickly decay into ...
- 557
0
votes
1
answer
108
views
Can a gauge theory with $SU(2)_{left}*SU(2)_{additional}$ symmetry contain confinement?
Consider a gauge theory with $SU(2)_{left}*SU(2)_{additional}$ symmetry.
By $additional$, I mean adding a new symmetry between an electron and a quark(like up quark and electron forming a doublet).
...
- 1,268
1
vote
1
answer
69
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Asymptotic freedom and momentum exchange
Why is the momentum exchange very high for low distances?
For sufficiently short distances or large exchanges of momentum
https://en.wikipedia.org/wiki/Asymptotic_freedom
While I think about ...
- 1,507
5
votes
1
answer
830
views
If quarks don't exist individually how can we say baryons are made up of three quarks?
We know the composite subatomic particles are made up of odd number of quarks (at least 3 for baryons ) or combination of quarks and antiquarks (mesons). My question is if they don't exist ...
user237285
1
vote
0
answers
178
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Four-fermion "contact" interactions differing from those arising from the Standard Model
In the 1998 article Compositeness Test at the FMC with Bhabha Scattering, it states that:
It was pointed out that the existence of quark and lepton substructure will be
signalled at energies well ...
3
votes
2
answers
730
views
Why doesn't infrared slavery provide a proof for quark confinement?
It is well known how and why the running coupling of QCD grows as we reduce energy or equivalently increase distance. Hence, if the effective color charge increases with distance then why doesn't this ...
- 17.8k
0
votes
1
answer
364
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masses and confinement
I sometimes read something like "..(..) masses are below/above the confinement scale(..)". I just ask plain: What does this mean in the way: How can masses be connected to the confinement scale and ...
- 1,507
11
votes
2
answers
299
views
Strong force between quarks that are out of causal contact
This is a rather artificial scenario, but it has been bugging me lately.
Background
Due to the confinement in QCD, quarks are bound in color-neutral configurations. Any attempt to separate a quark ...
- 3,947