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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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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How are quarks assigned color charge?

As always, I'll preface that I am wildly undereducated, so i may be overlooking something or be completely unaware of another relevant property. Color Confinement dictates that to "assemble" a baryon ...
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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 ...
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Why do mesons decay?

Why do mesons decay shortly while baryons are more stable? And why do mesons decay, meaning that there are unstable, while they formed because meson is more stable than the two corresponding quarks? ...
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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 ...
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Below which energy would the weak interaction become confining?

Claudson et al considered an alternative formulation of the standard model where the SU(2) interaction was strengthened to become confining below ≈ 300 GeV, above the electroweak scale. Consider if ...
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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 ...
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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 ...
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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,...
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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?
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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?
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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?
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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 ...
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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 ...
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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 ...
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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, ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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?
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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.
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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?
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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?
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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 ...
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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} ...
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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 ...
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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. ...
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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 ...
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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 ...
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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 ...