All Questions
10
questions
0
votes
1
answer
81
views
Possible cases of matter fields for $SU(2)$ theory which retains asymptotic freedom?
Let us assume $4$ spacetime dimensions.
QCD, the $SU(3)$ gauge theory with quarks as the matter fields, have the asymptotic freedom property as long as there are 16 quark flavors of mass below the ...
- 1,669
3
votes
1
answer
258
views
What makes the (non-abelian) strong interaction so special that it leads to confinement?
The strong interaction has a coupling constant of $\alpha_s(91GeV)\approx 0.1$ whereas the weak interaction has a much lower coupling constant $\alpha_w \approx 10^{-6}$. Both theories are non-abelian ...
- 9,778
1
vote
1
answer
157
views
How do you reconcile quark masses with notion of confinement?
In trying to understand exactly what confinement means, I have been reading 't Hooft s original paper on 2D QCD at large $N$. In the paper he shows that the quark propagator pole is moved to infinity, ...
- 744
5
votes
1
answer
375
views
How can we tell a theory is confining?
Physically, I understand what it means for a theory to be confining. The elementary particles are not observable, but only composite particles are. The classic example is QCD, where quarks are ...
- 3,514
5
votes
1
answer
185
views
Would Color Confinement apply in higher dimensions?
As I understand it color confinement comes from the fact that as the distance between two color charges increases the color potential energy increases, instead of decreasing, and the energy needed to ...
- 2,001
7
votes
1
answer
442
views
Is Yang-Mills theory confining in any dimensions?
What is the current understanding of Yang-Mills theory (pure non-Abelian gauge theory without matter field) in the infrared limit? (To avoid the subtlety of renormalizability, we may restrict our ...
- 11.9k
5
votes
1
answer
262
views
Would the existence of more than 16 quark flavors make QCD deconfinning?
Consider the QCD beta function. Its expansion in powers of the coupling is
$$\beta(\mu)=-(\beta_0a(\mu)+\beta_1a^2(\mu)+\ldots)$$
where $a=\alpha/4\pi$. For simplicity let's neglect everything but ...
- 6,067
4
votes
0
answers
322
views
Why is QCD hard to solve if I know the beta functions?
Why is it still hard to solve QCD if we know the beta functions of the coupling? Aren't only the loops causing problems? And am I not able to write every possible interaction exact at tree-level with ...
- 2,147
16
votes
1
answer
2k
views
Are "confinement" and "asymptotic freedom" two sides of the same coin?
On Wikipedia it says that the two peculiar properties of quantum chromodynamics (QCD) are: confinement and asymptotic freedom.
Asymptotic freedom is the idea that at low energies we cannot use ...
- 5,228
5
votes
1
answer
175
views
Could quarks be free in higher-dimensional space than 3D?
Reading this answer, I now wonder: if quarks are confined by $r^2$ potential, could their potential allow infinite motion in higher-dimensional space?
To understand why I thought this might be ...
- 29.1k