Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [confinement]

Color confinement is the concept that particles that possess color charges (quarks and glouns) can not be found freely, and only color-free combinations can be observed.

3
votes
1answer
48 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 ...
1
vote
1answer
43 views

Why do we have 3 quantum colours?

I understand the need to invoke colour as another quantum state to explain the observation of uuu ddd and sss baryons. I just wanted to know if there was some other property which explains why we only ...
7
votes
2answers
109 views

Why does the divergence of a QFT's coupling constant under RG flow trivialize the theory if it occurs in the UV but not in the IR?

When you first learn quantum field theory, at some point you calculate the beta function (to leading order) for a renormalizable coupling constant of some theory like $\varphi^4$ theory, Yukawa theory,...
0
votes
3answers
77 views

Can a quark quantum tunnel outside a nucleus?

I read that a particle wavefunction can extend over a thin barrier and there is a probability of finding it over the barrier even though it doesn't have the necessary energy, what about quark?
2
votes
1answer
50 views

How and why is the pentaquark stable if it consists of 4 quarks and an antiquark?

If matter and antimatter annihilate each other, why is the pentaquark stable since quarks are matter and the antiquark is antimatter?
0
votes
0answers
36 views

Why are mesons only made of a quark-antiquark pair? [duplicate]

Why can't we have a meson made of two quarks, why does there have to be the antiquark too?
0
votes
1answer
53 views

Clarification about confinement of colour charged objects

In lecture today we were reviewing the QCD lagrangian, and discussing hadronic wavefunctions. My lecturer said that QCD alone allows for states of colored hadrons, however because we do not see ...
3
votes
2answers
134 views

Spaghettification on quarks?

Imagine a nucleon falls into a black hole, I would expect the gravitational force acting on each quark to be drastically different but due colour confinement wouldn't there more pairs of quarks being ...
0
votes
0answers
76 views

Why is color confinement a difficult problem?

Assuming color force follows a constant rule of force instead of an inverse square rule of force. And that red, green and blue are all attracted to each other. Why is color confinement considered a ...
3
votes
0answers
54 views

What is the relation between the Gribov problem and color confinement?

I have heard that the Gribov problem is in some way related to color confinement (For instance: Gribov copies and confinement). Although I understand what both the Gribov and confinement problems are, ...
3
votes
2answers
356 views

How do we know that gluons travel at the speed of light?

Since gluons are located within nucleons and immediately outside of them, how do experiments determine parameters like their speed? Is it possible we could be assuming they travel at the speed of ...
1
vote
0answers
99 views

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 ...
4
votes
1answer
165 views

How to “build” a proton

Sabine Hossenfelder in her column The End of Theoretical Physics As We Know It made the following statement: For example, we have a perfectly fine theory that describes the elementary particles ...
1
vote
1answer
225 views

Can we find a free gluon?

I have read these questions: Quark intrinsic angular momentum and the Proton Spin Crisis About free quarks and confinement https://en.wikipedia.org/wiki/Gluon And it made me curious. I understand ...
0
votes
1answer
57 views

Difference between boundedness (electrons around nuclei) and color confinement (quarks)

I have read these questions: How does the orbiting of electrons around nuclei START? Bound electrons don't move, right? Do different orbitals overlap in multielectron atom? What is the ...
1
vote
1answer
36 views

How does it make sense to talk about, for instance, quarks traveling at near lightspeed while confined to a volume as small as a proton?

How does it make sense to talk about, for instance, quarks traveling at near lightspeed while confined to a volume as small as a proton? The distances are so small, and the speed so high, that the ...
0
votes
1answer
46 views

What happens if I add a single quark to a system of hadrons? [duplicate]

In pure QCD in the confinement phase what happens if I add to a system of baryons, which are quarks in the condensed phase, another quark? It doesn't have any quark or antiquark to form a baryon or a ...
4
votes
1answer
169 views

Is there confinement in the Gross-Neveu model?

The Gross-Neveu model is a simple quantum field theory in 2 space-time dimensions that is considered a toy model for QCD, in the sense that it realizes asymptotic freedom, chiral symmetry breaking ...
1
vote
0answers
155 views

Wilson Loops and Confinement in QED

In [1] Kenneth G. Wilson proposed a mechanism for confinement using lattice paths what leds him to the concept of Wilson loop. It seems to me that he is using mainly a single abelian field. He says ...
0
votes
1answer
152 views

Has experimental search for free fractional electric charge elementary particles been put to an end?

Since Quantum Chromo-Dynamics theory has been supposed to explain quarks confinement, has experimental search for free fractional electric charge elementary particles been put to an end? If not, what ...
2
votes
0answers
88 views

What's the meaning of QCD phase transition temperature?

I read about the QCD energy level in various sources, eg: Wikipedia, and this gives a phase transition temperature of about 200 MeV, above which quark confinement breaks down and we may observe ...
2
votes
2answers
215 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 ...
16
votes
1answer
1k views

Inverse square rule for strong forces

Most of the forces induced by a point particle follows the $1/r^2$ rule. Then why does the strong force not obey it?
0
votes
2answers
74 views

There're some new (at least 2010) review about QCD?

I'll start my master's in the next semester and I'll study QCD. I want a review for learn QCD and know what's going on in this field. I more interested in confinement.
0
votes
2answers
112 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?
1
vote
1answer
109 views

What is the significance of finding quark-antiquark pairs in hadrons?

What is the significance of finding quark-antiquark pairs in hadrons? Does is have any effect, and hypothetically, could you pull the 3 quarks in a hadron apart so they formed 3 mesons?
0
votes
1answer
70 views

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 ...
0
votes
1answer
62 views

If the $SU(3)$ Noether charge is not gauge-invariant how can we say Hadrons are colorless?

The Noether charge associated with global $SU(3)$ invariance is \begin{equation} J^{\mu}_a=-f_{abc}F_c^{\nu\mu}A_{b\mu}-i\frac{\delta \mathcal{L}_{Matter}}{\delta D_{\nu}\psi}t_a\psi \end{equation} ...
3
votes
1answer
93 views

Is direct observation of strong and weak force ruled out by quantum field theory?

In quantum field theory electromagnetic radiation is described by a theory with an abelian gauge symmetry while the weak and strong force are described by theories with non abelian gauge symmetry. We ...
2
votes
2answers
86 views

The distinctions between $\mathrm{U}(1)$ and $\mathrm{SU}(3)$ massless bosons

The force carrier particles that mediate the electromagnetic, weak, and strong interactions are called gauge bosons. It is known that the gauge bosons in EM force and strong force are both massless. ...
3
votes
1answer
419 views

Wilson loops, confinement and chiral symmetry relations

As per my limited understanding of confinement, I understood it as phenomenon between fermions of a gauge theory, such as $SU(3)$ gauge theory in the low energy limit (where the coupling constant ...
1
vote
0answers
46 views

Are there models for QCD confinement in non supersymetric theories?

I was reading Shifman papers about QCD confinement. He usually use methods from condensed matter and string theory to solve the problem using the gauge/string. Is there some similar approach from ...
3
votes
0answers
213 views

Protons and Neutrons inside the Nucleus

I know that the strong nuclear force holds quarks together to form protons and neutrons, as long as their color charges add up to white, so then how does the strong force simultaneously hold the ...
6
votes
1answer
212 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 ...
1
vote
0answers
42 views

Could we draw field lines for colour charge?

Electromagnetic charge can be represented with field lines. These are pleasingly intuitive and can be used to visualise Gauss's Law and Maxwell's Laws. Later on Gauss and Maxwell get rolled into a ...
1
vote
1answer
168 views

Why are there no free quarks? [duplicate]

Why are there no free quarks? I am not looking for "because you can't pull them apart". If you have a problem understanding the question, then understand it as: Were there ever free quarks in the past?...
12
votes
1answer
426 views

What is a precise mathematical statement of the Yang-Mills and mass gap Clay problem?

I am a mathematician writing a statement of each of the Clay Millennium Prize problems in a formal proof assistant.  For the other problems, it seems quite routine to write the conjectures formally, ...
2
votes
1answer
150 views

Nonabelian version of Polyakov's confinement analysis for compact gauge theory

Alexander Polyakov studied the confinement of Abelian compat U(1) gauge theory without matter field in 1975 at "Compact gauge fields and the infrared catastrophe. Phys.Lett. B59- 82–84 (1975)," see ...
0
votes
1answer
193 views

What's the difference between these two 'process'?

In my text book it talks about about protons colliding: to demonstrate the idea of pair production and quark confinement. In both scenarios two protons collide (the energies of each are not stated ...
2
votes
0answers
94 views

Is the confinement mechanism understood in 1+1 QCD ('t Hooft's model)?

I was following the coleman lectures on "Aspects of symmetry" particularly the chapter about the 't Hooft's model. Then I have wandered into older papers like the 't Hooft's papers and many others. ...
1
vote
0answers
60 views

Why does Monopole in $D=3+1$ not drive a compact $U(1)$ gauge theory into a Confined Phase?

In compact $U(1)$ gauge theory, it has confined/deconfined phase. For $D=2+1$, monopole (2$\pi$-flux) event can always drive a system into a confined phase, as shown by duality mapping to a Sine-...
13
votes
3answers
3k views

If free quarks can't exist, how did the universe form?

As I understand, the Big Bang started with a photon gas that then created the other particles. Thus obviously there would be some free quarks in the early Universe unless quarks are always created in ...
7
votes
2answers
324 views

What does an accelerated body's *interaction* with Unruh radiation look like in an inertial frame?

(Note: I'm only considering flat spacetime in this question.) The Unruh effect is that the quantum state that looks like the vacuum in an inertial frame looks like a thermal bath of particles in a ...
0
votes
0answers
27 views

Why has there never been measured a free quark or gluon, but only objects that are built out of them, such as mesons and baryons? [duplicate]

Why do we not observe any free quarks or gluon, but only particles that are built out of them, such as mesons and baryons? How does this phenomenon emerge from QCD?
2
votes
1answer
185 views

Color confinement and integer electric charge?

Quarks have electric charges proportional to one third of the elementary electric charge, but both mesons and baryons have integer electric charge. Is there some deep explanation from a more ...
1
vote
1answer
182 views

Low dim physics: Examples of confinement-deconfinement phases of U(1) gauge theory in 2 dimensions

Please provide some examples of confinement-deconfinement phases of U(1) gauge theory in 2 spacetime dimensions (Low dimwnsional physics). U(1) gauge theory can be: pure U(1) gauge theory, or U(1) ...
7
votes
1answer
156 views

Minimal field theory of confinement

Quantum chromodynamics (QCD) is an $SU(3)$ gauge theory that exhibits confinement. Which properties of QCD lead to confinement? Is it the gauge symmetry, the coupling strength, or something else? ...
7
votes
1answer
359 views

Why do we have a non-zero quark vacuum condensate even though the QCD coupling goes to zero in the deep infrared?

It is well-known that QCD has a Landau pole at $\Lambda_{\rm QCD}\sim 200$ MeV, which means that the perturbative QCD coupling becomes strong at this scale. Conventionally, this is claimed to be the ...
1
vote
0answers
14 views

What is the asymptotic behavior of the two quarks interaction in the limit of small distances and in the limit of long distances?

quantum chromodynamics. It is known that at small distances two quarks do not interact and interaction remains constant at large distances. So the question stands: What is the asymptotic behavior of ...
1
vote
0answers
320 views

What is quantum confinement in simple terms? [closed]

I have read quite a few explanations of quantum confinement, but did not understand them. I have only a beginning understanding of quantum mechanics. What is quantum confinement in the simplest ...