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.

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Chemical potential interpretation for QCD phase diagram

I'm studying the QDC phase diagram at finite densities and I'm having some trouble understanding the role of the chemical potential. It's clear how, if I increase the density of particles at $T=0$, I ...
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Quantum chromodynamics - why are there no $rrb$ or $ggr$ terms?

$$\Psi_{colour}^{qqq} = \frac{1}{\sqrt{6}}(rgb + gbr + brg -grb - rbg - bgr)$$ My lecturer stated that there cannot be any $rrb$ or $ggr$ terms in the expression above. I would like to understand what ...
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Can we say tension is the ability to generate interference by this paper?

https://arxiv.org/abs/1206.2021 Abstract : We propose a method for measuring the string tension in gauge theories, by considering an interference effect of mesons, which is governed by a space-time ...
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Area and perimeter

Apparently (?), a line operator over a very large loop with length $L$ can obey either perimeter law or area law, $-\log\langle U\rangle\sim L^a$ with $a=1,2$, respectively. We call these options &...
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In the history of the development of the standard model was there a version in which quark-antiquark pairs or flux tubes were the fundamental particle [closed]

Based on the observations of color confinement and no free quarks, I'm wondering if instead of a having quarks as fundamental particles, during development of the Standard Model was there ever a ...
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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?
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What would happen to a quark if it could be isolated, into what particles it would change? [closed]

WP defines as quantum charge the $-\frac{1}{3} e$ charge value of the down quark and as elementary charge the -1e of the electron. The elementary quark particle cannot be isolated in the lab and its ...
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Local order parameter for confinement in gauge theories

I would like some help clarifying what Zinn Justin is saying in his book "Quantum Field Theory and Critical Phenomena" p.805 on detecting confinement of gauge theories. In particular, I ...
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What is the current status (October 2021) of the Yang-Mills existence and mass gap problem?

One of the famous "millennium prize problems" is the "Yang–Mills existence and mass gap" problem, which in its official description by E. Witten and A. Jaffe has the following form:...
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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 ...
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Why does color confinement fail at high temperatures?

The explanation for color confinement that I see everywhere is that as the distance between quarks increases, the strong force between them approaches a constant value. Once the quarks get far enough ...
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What is confinement?

I just got confused about the meaning of confinement in QFT. The naive definition is that in QCD one cannot observe isolated quarks and gluons. This is a trivial statement because in any gauge theory ...
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Is a 6-quark particle viable?

It is my understanding (which may be flawed) that protons and neutrons are stable because the 3 (R, G, and B) quarks form a "white" color singlet. Wouldn't 6 quarks or even 9 quarks create ...
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Is it possible for an isolated quark to exist if it's bound to one or more non-virtual gluons to render the system color neutral?

We know color-neutral bound systems of quarks exist in the form of hadrons, we suspect color-neutral bound systems of gluons exist in the form of glueballs, we have a candidate particle which may be ...
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What units is strong nuclear charge measured in? [duplicate]

Do particles have a strong nuclear charge in the same way as they have electric charge? If so what unit would be used to measure this? Would it be measured in Coulomb for instance?
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Primordial color charge fluctuations that failed to die out due to cosmic inflation

We know that ripping the quarks in a hadron apart will not give us free quarks, but rather new (anti-)quarks are generated that neutralize the color charges of the quarks. We also know that the total ...
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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 ...
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What happens to the individual quark(s) produced in a $W$ boson decay 'chain'?

Just over two-thirds of the time, a $W$ boson decays into quarks, usually an up quark and a down antiquark... Right? Since quarks hate being alone, what happens next? Does the up quark pull a single ...
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In the deconfinement phase, there are absolutely no interactions between the particles?

The Wikipedia article on Deconfinement says: "In physics, deconfinement (in contrast to confinement) is a phase of matter in which certain particles are allowed to exist as free excitations, ...
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What would happen to a lone quark?

If a quark simply popped into existence, what would happen to it? Or is this question unanswerable for some reason (e.g "a quark, by definition, exists with other quarks, and has no mathematical ...
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Do hadrons have color moments?

Hadrons have electrical moments since they are made up of both positive and negative charges. Water molecules have dipole moments for the same reason even though they are electrically neutral. Since ...
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Why are there no composite particles with fractional charges?

Mesons are composed of a quark and an anti-quark, so no fractional charge is possible mathematically. Baryons are composed of three quarks, no anti-quarks mixed in with quarks, so no fractional charge ...
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About the validity of the dilute gas approximation

In the compact QED (cQED) in $(2 + 1)$ dimensions confinement /deconfinement property is described in terms of boundness of monopole-antimonopole pairs (Berezinskii-Kosterlitz-Thouless phase ...
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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? ...
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How can we split a proton? [closed]

I have heard the following statements: Quarks always exist in a group of 2 or 3, and can not stand alone. Protons are made up of 2 up quarks, and 1 down quark. Quantum mechanics allows us to entangle ...
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How would quarks behave in the event of 'The Big Rip'?

I have always heard that you can't get a quark by itself because "the energy required to split them apart is enough to create another." But, in the case of The Big Rip, the idea is that ...
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How does the mere movement of gluons keep quarks together?

You know the strong force (the one that keeps quarks together). Well it works by exchanging gluons right? So how does that force keep the quarks together? I mean you can imagine that process as three ...
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What happens when one separates a quark-antiquark pair?

in particular, if the distance is more than about 1 fm?
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In a Big Rip scenario, would color confinement cause a singularity to form?

The energy in a gluon tube between quarks increases approximately linearly with the distance between them, and when that energy is sufficient to spawn a quark-antiquark pair out of the vacuum, it does ...
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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_{\...
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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 ...
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Can a baryon consist of two quarks and an antiquark? Or a pentaquark be made of three quarks and two antiquarks? [duplicate]

I suspect these particles exist, but are extremely short-lived, even compared to other unstable, exotic particles...
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Validity of Seiberg-Witten theory and the understanding of notion "Effective field theory"

I am reading "An Introduction to the Confinement Problem" book by Jeff Greensite https://books.google.ru/books?id=atwRBwAAQBAJ&printsec=frontcover&hl=ru#v=onepage&q&f=false, ...
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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). ...
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Permitted bound states in extended QCD color group $SU(4)$

I'm very much curious about the possible quark combinations to form bound states in $SU(4)$ QCD. We already know Wilson has proven that only colorless combinations can arise in $SU(3)$ of these ...
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Abelian theory with confiment in 4d (Polyakov book)

In chapter 4.3 of Gauge Fields and Strings Polyakov study effect of monopoles. He make few statements: In 4d Maxwell theory with monopoles, exist phase transition, if $e_0^2> e_c^2$ it is ...
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At the Big Bang, when particles were created, could free standing quarks (not bound in a hadron) have been created and remain alone today?

You can't pull a quark out of a hadron, but at time $T = 10^{-43}$ seconds or shortly thereafter, when all particles were created, wouldn't all quarks be individual, and not grouped into hadrons, (...
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Phase transition in 3+1 abelian theory

In historical paper A View From the Island, A. M. Polyakov wrote at 6th page: In the abelian case, these dislocations turned to be just the world lines of magnetic monopoles and I predicted the ...
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Models of confinement based on negative mass carriers

In the old Yukawa model of nuclear forces, it was proposed that short-range interactions were mediated by exchanges using massive force carriers (originally, mesons were proposed for this). If one ...
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Simple "toy-model"-like explanation of quark confinement (QCD) and accompanying math

I have a qualitative understanding of quantum chromodynamics within nucleons and between nucleons, but I do not understand the math behind some of the physics like quark confinement. What is the math ...
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Quark confinement mechanism

As far as I understood: Quark confinement states that observing individual quarks is not possible, color charged quarks are confined into hadrons. As we try to pull them apart, force between them ...
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Is it possible to derive a non-mass gap from the Yang-Mills action? [duplicate]

The action: $$J=∫Tr(F∧⋆F).$$ Is it possible to find the non-mass gap property from the Yang mills action? If so, how?
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What is quark 'confinement' in the context of Yang-Mills Theory?

In the context of Yang Mills Theory, what is quark confinement? Please try to explain as simple as possible (obviously without being too general)
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Why there is no such a thing as colour moment?

I was busy google about different types of electric and magnetic dipole moment then a thought suddenly striked me, why there is no colour multipole moment?
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Why hasn't Peter Higgs solved the Yang-Mills prize problem?

The Higgs mechanism gets rid of the mass gap problem, and it's been experimentally proven, so why is there still a problem? Why are the million dollars still up for grabs?
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Can particle with fractional charge exist in isolation?

Since quarks are ruled out I wonder if it is possible for free fractional charge to exist not counting virtual particles?
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What happens when somebody solved mass gap problem like ultraviolet catastrophe? [closed]

Just curious if somebody came along and proposed a good mathematical solution to the millennium problem but it is not intuitive at first, what happens then? this person can rigorously proof the ...
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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, ...
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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 ...
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Why do we still call the electron charge the elementary (EM) charge?

The electron is an elementary particle, part of the SM, pointlike, with no substructure, or spatial extent. Its intrinsic properties include its EM charge, which we still call the elementary charge. ...
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