Why are gluons considered to be elementary particles?

Click For Summary

Discussion Overview

The discussion revolves around the classification of gluons as elementary particles within the framework of the Standard Model of particle physics. Participants explore the nature of gluons, their properties, and their relationship to mesons and other force carriers, focusing on theoretical implications and conceptual understanding.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants argue that gluons are not truly fundamental particles but rather composite entities akin to mesons, which are quark-antiquark pairs.
  • Others assert that gluons are fundamentally different from mesons, highlighting that mesons have mass and are color-neutral, while gluons carry color charge and do not have the same properties.
  • A participant questions the classification of W bosons as mesons, suggesting that they too can be depicted similarly, but this claim is contested.
  • One participant notes the distinction between the quantum states of gluons and mesons, emphasizing that the representation of gluons in terms of color charge does not equate them to mesons.
  • Another participant discusses the mathematical representation of quark-antiquark states, explaining the difference between color singlet and color octet representations, which relate to mesons and gluons, respectively.

Areas of Agreement / Disagreement

Participants express disagreement regarding the classification of gluons and mesons, with no consensus reached on whether gluons can be considered as mesons or if they are fundamentally different entities.

Contextual Notes

The discussion includes various assumptions about particle properties and representations that are not fully resolved, particularly regarding the implications of color charge and the nature of force carriers.

Sophrosyne
Messages
128
Reaction score
21
Gluons are often depicted as fundamental particles in the Standard Model. But in looking at their mechanism, it seems they are not really fundamental particles in the sense that they are fundamental, indivisible, building blocks. They are mesons- a composite quark-antiquark pair, where their spin adds up to zero and therefore they act as gauge bosons.

And speaking of that, it seems even the weak force, the W bosons, can also be depicted equivalently as mesons, can't they?

Am I misunderstanding this somehow?
 
Physics news on Phys.org
Sophrosyne said:
They are mesons- a composite quark-antiquark pair
They are not. Mesons have mass, mesons are color-neutral, mesons have excited states, and various other properties that differ from gluons.
Sophrosyne said:
And speaking of that, it seems even the weak force, the W bosons, can also be depicted equivalently as mesons, can't they?
It cannot.
 
Sophrosyne said:
They are mesons- a composite quark-antiquark pair, where their spin adds up to zero and therefore they act as gauge bosons.
where did you get that information?
The Standard Model particles are the following:
Vector Bosons (Spin=1) : W/Z-bosons [W/Z], photons [γ], gluons [g]
Scalar Boson (Spin = 0) : Higgs [H]
Fermions (Spin=1/2):
__leptons don't interact via strong interactions:
electron (e), muon (μ), tau (τ) and the respective neutrinos (νe,μ,τ)
__quarks do interact via strong interactions:
up (u), down (d), charm (c), strange (s) , top (t) , bottom (b)
 
I see. I guess I was seeing the use of mesons as force carriers for the inter-hadron interactions, and I also saw that gluons carry color charge in eight different types even for the inter-quark interactions, represented by the "color octet" states. These are represented in a quark-antiquark representation, and thought that was the same thing as a meson. But that just seems to be the quantum state of the gluon, not a meson.
 
The quark-antiquark colour representation is a 9-dimensional representation (since it is the product of two 3-dimensional ones). It can be split into a colour singlet, which is the colourless trivial representation of mesons, and a colour octet - the same representation that the gluons transform according to.
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
5K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 23 ·
Replies
23
Views
5K
  • · Replies 11 ·
Replies
11
Views
4K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K