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Questions tagged [gluons]

Gluons are vector gauge bosons that mediate strong interactions of quarks and themselves in quantum chromodynamics. There are eight of them, as they are in the adjoint representation of the SU(3) color group, and carry the color charge of the strong force, which results into the binding of hadrons.

Gluons are vector gauge bosons that mediate strong interactions of quarks and themselves in quantum chromodynamics. There are eight of them, as they are in the adjoint representation of the SU(3) color group, and carry the color charge of the strong force, which results into the binding of hadrons.

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Why have our eyes not evolved to see "gluons"?

The photons are the propagators for QED, and we rely on photons to see the world around us. The gluon is the propagator in QCD. Why have our eyes not evolved to see gluons (either on top of being able to "see" photons, or instead of)?
DarthPlagueis
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Why are gluons believed to be massless?

Earlier questions under a similar title referred to the short range of the strong force. My question is completely different. I'd like to know why gluons are considered massless in the Standard Model (regardless of the range of the strong force).…
safesphere
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How (or when) do gluons change the color of a quark?

I know a baryon is only stable when it contains a quark of each color. And as far as I know, the gluon essentially changes the color of a quark and moves onto the next, and this is what holds the particles together. But in the process of the gluon…
Vedvart1
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How can a massless boson (Gluon) mediate the short range Strong Force?

I thought massless particles were mediators for long range forces such as electromagnetism and gravitation. How can the massless gluon mediate the short range strong force?
user4884
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Why $SU(3)$ and not $U(3)$?

Is there a good reason not to pick $U(3)$ as the colour group? Is there any experiment or intrinsic reason that would ruled out $U(3)$ as colour group instead?
IamZack
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If massless objects ALWAYS travel at the speed of light and gluons are massless, how are they trapped within hadrons without a need for event horizon?

From what I heard, unless we have some kind of other influence, all things and light move at the straight lines in spacetime. If they have a mass, then they can never reach the speed of light, but all the massless ones are constantly traveling at…
Kusavil
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Why so much kinetic energy inside a proton?

I'm reading 'Waves in an impossible sea' by Matt Strassler - a very good, popular science book, by the way - and he explains that the rest mass of a proton mostly comes from the kinetic energy of the quarks and gluons whizzing around. But I don't…
j4nd3r53n
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why is there no ninth gluon?

A teacher of mine told me once that there were no ninth gluon because such a one should be white and interact infinitely far, and no one has been observed. Is there also a theoretical reason?
Isaac
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Non-existence of gluon singlets: Any recent theoretical progress?

An unanswered question from last year (2012) on gluon singlets asked whether there is any theoretical explanation for the experimental absence of the ninth or colorless (singlet) gluon. This is the gluon that, if it existed, would give allow the…
Terry Bollinger
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Do color-neutral gluons exist?

If I'm correct a quark can change color by emitting a gluon. For example a blue up quark $u_b$ can change into a red up quark by emitting a gluon: $$u_b \longrightarrow u_r + g_{b\overline{r}}$$ (Here, the subscript indicates color and…
romeovs
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What's the difference between a meson and a glueball?

There is a blog post by Matt Strassler about the structure of hadrons. He contrasts the "conventional" picture of hadrons shown below: with one that he considers to be more accurate: From the second figure, one would be led to believe that there…
Brian Bi
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Why are gluons massless as their range is finite?

The range of electromagnetic waves and gravitational force is infinity and the particles exchanged during these interactions are photons and gravitons respectively. Both are massless following the relation: the range is inversely proportional to…
Vanshika Dhiman
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What is the role of the color-anticolor gluons?

Ignoring for the moment the experimental necessity of eliminating the gluon singlet state, the nine "raw" gluon color components form two quite distinct sets. The first set consists of the six (color,anti-other-color) components: $r\overline{g}$,…
Terry Bollinger
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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 an hybrid meson bound to a gluon. My question is…
Adam Lincoln Steele
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Can photons be converted to gluons

Is there any method we can use to convert a photon into a gluon, as they are similar in many respects. For instance, if we pass a $100\,{\rm keV}$ photon through a strong electric field, can this photon convert into a gluon?
Mahmoud
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