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glueball8
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Can graviton possible act like gluon ball? Why not?
This is not obvious. One can argue that "there are more gluons in a more massive hadrons". Anyway, the idea has yet other caveats.masudr said:This reason this cannot be the graviton is because it would couple to all baryons with the same strength (since all baryons are colourless), and yet baryons have different mass and should couple differently to the graviton.
This also is not obvious at all ! Despites extensive searches (to which I participate, I am not saying this is worthless), we have only very indirects mixing hints in only a few mesons (not even to mention pure glueballs). Besides, it is sometimes dangerous to jump to the conclusion "because something is not forbidden, it must be realized in Nature". Not all models of confinements agree on the possibility of free glueballs. The presence of light quarks, either in the valence or only in the (virtual) sea, is sometimes believed to be essential.Since there is an allowed 3 gluon vertex and 4 gluon vertex in QCD, we can in principle have a bound state of gluons.
Bright Wang said:Can graviton possible act like gluon ball? Why not?
No, as indicated by arivero the graviton has spin-2 (couples to the EMT). The gluon has spin-1 (vector).Orion1 said:
Affirmative, by setting their fine structure constants to equivalence:
Gravitational fine structure constant equivalent to strong fine structure constant:
[tex]\boxed{\alpha_g = \alpha_s}[/tex]
Ah but that is very interesting ! It was not clear from the beginning of the discussion anybody was interested into the AdS/CFT correspondence and the so-called "RHIC fireball". As far as I am aware, the first serious (courageous) attempt in this direction was The RHIC fireball as a dual black hole. This line has been very productive. A recent review can be found in Introduction to String Theory and Gauge/Gravity duality for students in QCD and QGP phenomenology.Orion1 said:However, I would still defend gluon-gravitational Grand Unification for a degenerate QCD QGP plasma (ball), which was my original presumption for a 'gluon ball'.
I don't want to hack this thread but... I'll do it anyway :tongue2:arivero said:On other hand, if you only want to mimic attractiveness of like charges, then a spin 0 glueball could do the trick (again ,were it massless).
humanino said:I don't want to hack this thread but... I'll do it anyway :tongue2:
How would you write down a lagrangian involving only a scalar field, supposed to be the most relevant component of the graviton field in a certain low energy/long distance limit, while keeping non-abelian effects ?
I was thinking to try someything like
[tex]S=\int d^4x \left[\partial h\partial h+\sqrt{G}h\partial h\partial h+Gh^2\partial h\partial h+\cdots + \sqrt{G}hT \right][/tex]
by directly replacing in the usual expansion the graviton with a scalar field. Do I make sens ? :uhh:
Thank you for you answerblechman said:we found that we can always kill such "nonabelian" terms with a (nonlinear) field redefinition
Arg, I just bought Kiefer's books and barely began itCheck out Tomas Ortin's textbook "Gravity and Strings" - it talks about these kinds of theories.
humanino said:Thank you for you answer
I will keep playing with it and try to redefine my field to "gauge" away my non-abelian terms. Intuitively, it does seem odd because any non-abelian group acting on my scalar could only do so trivially. I expected this to be fishy actually.
Arg, I just bought Kiefer's books and barely began it
So little time...
Bright Wang said:Hmm I'm in high school. So I don't get the math. Can anyone explain the concepts?
Yes, that's why I put "gauge" and not gaugeblechman said:it's NOT a "gauge" issue - it's a field redefinition. quite different. there's no symmetry argument, it's just that these nonlinear terms can all go into a sort-of wave-function renormalization constant, and are therefore irrelevant; that is: they don't lead to any physical observables. the "Z" I mention is NOT a transformation.
humanino said:Yes, that's why I put "gauge" and not gauge
Thanks for the correction though.
"any non-abelian group acting on my scalar could only do so trivially."
Bright Wang said:Oh hmm I never asked if Gluon and graviton are the same. It was meant that if its possible for graviton to have the "Ball" properties and as in it interact with it self.
Thanks for the reply
A graviton is a hypothetical particle that carries the force of gravity in quantum theories. A gluon is a subatomic particle that carries the strong nuclear force between quarks.
Gravitons and gluons are fundamentally different particles with different properties. Gravitons are thought to have zero mass and interact with all particles, while gluons have mass and interact only with quarks.
No, gravitons and gluons serve different purposes in the Standard Model. Gravitons are not included in the Standard Model, and gluons play a crucial role in the strong nuclear force.
Yes, gravitons and gluons can coexist. They are both fundamental particles that exist in the universe and interact with other particles in different ways.
There is currently no experimental evidence for the existence of gravitons, as they have not yet been detected. However, there is strong evidence for the existence of gluons, as they have been indirectly observed through experiments such as particle colliders.