I have read these questions:

Quark intrinsic angular momentum and the Proton Spin Crisis

About free quarks and confinement


And it made me curious.

I understand that quarks can only be found in confinement, and that gluons create flux tubes, if we want to separate them. When we want to separate quarks, the energy needed will not decrease with distance, but will remain constant and after a while it will be enough to create new quarks.

But I did not find anything about gluons, can we find free gluons? Is that what a gluon ball is? Can we find those free?


  1. Can we find free gluons (at normal energy levels)? Can we find free gluon balls?
  • 2
    $\begingroup$ It says right in the confinment section, gluons also carry volor charge and so must obey confinement just like quarks $\endgroup$ – Triatticus Jun 22 '18 at 17:28
  • $\begingroup$ Yes but they create a gluon ball, and that might exist free? $\endgroup$ – Árpád Szendrei Jun 22 '18 at 18:00
  • 1
    $\begingroup$ A glueball is a confined state that is also colorless, but made of strictly gluons and doesnt have valance quarks $\endgroup$ – Triatticus Jun 22 '18 at 18:08

Always start with the wiki:

In particle physics, a glueball (also gluonium, gluon-ball) is a hypothetical composite particle.1 It consists solely of gluon particles, without valence quarks. Such a state is possible because gluons carry color charge and experience the strong interaction between themselves. Glueballs are extremely difficult to identify in particle accelerators, because they mix with ordinary meson states.

Here is a talk on the subject :, for a proposed experiment to find glueballs.

Gluon jets have been measured, fitting the predictions of QCD models, but they are jets of particles, as gluons themselves are colored, as observed in the comments and cannot be free.


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