Why eight gluons

One must really understand something about SU 3. This is the symmetry group of the strong force. What this means is that, as far as the strong force is concerned, the state of a particle is given by a vector in some vector space on which elements of SU 3 act as linear in fact unitary operators. We say the particle "transforms under some representation of SU 3 ".

This gives a 3-dimensional representation of SU 3. Quarks transform under this representation of SU 3 , and because it's 3-dimensional we say quarks come in 3 colors: red, green and blue. This is just an amusing way of talking about the 3 column vectors. Alternatively, we could let elements of SU 3 act on row vectors by multiplication on the right. Antiquarks transform under that representation, and since it is also 3-dimensional we say they come in three colors as well: anti-red, anti-blue, and anti-green.

This is just an amusing way of talking about the 3 row vectors. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Eight gluons, what are the properties of two of them? Ask Question.

Asked 1 year, 2 months ago. Active 1 year, 2 months ago. Viewed times. If they are colorless, can they exist in isolation? Improve this question. Madman Madman 31 2 2 bronze badges. I think I understood the reason it is disallowed but I don't remember it now. All 8 gluons are their own antiparticles. See en. I thought only one part would be used. It's not symmetrical. I guess I just don't get the concept of adding states and especially multiplying them by the square root of 2.

Show 3 more comments. That will take a mathematician to properly explain. Just give it some time, and others will pitch in as well. Some questions, like your last one, just don't have simple and straightforward answers, and I am not a mathematician, so I won't pretend that I can give a good answer to it.

Originally Posted by tk Did you read the reply there to this same question? Depending on what you consider an explanation, the article linked to there is probably as good as it gets, with an appeal to Occam's Razor which I'll paraphrase as "a particle that doesn't interact with anything might as well be treated as not existing, so farewell, ninth gluon".

QCD is notoriously difficult, and there are limits to what you can do and show without some pretty high-level maths. You can do everything right, strictly according to procedure, on the ocean and it'll still kill you, but if you're a good navigator at least you'll know where you were when you died. Originally Posted by Strange.

A naive way of thinking of this might be to consider that there is a gluon as an intermediary between each pair of colors.