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I Do glueballs of spin-2 mediate forces?

  1. Oct 11, 2016 #1
    gluons can form glueballs, and glueballs can have spin-0 and spin-2

    as a composite boson of spin-2, does it mediate new forces/interactions, and would a spin-2 glueball always be attractive the way gravitons are?

    do spin-0 glueballs form a condensate similar to the higgs field?
     
  2. jcsd
  3. Oct 11, 2016 #2

    mfb

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    Staff: Mentor

    "It has some propery in common" does not mean it is the same, it does not even mean any other property is shared. This is a general comment, you jump onto this overextrapolation in nearly every thread.
    There are atomic nuclei and atoms that share this property. Do you see them mediating forces?
     
  4. Oct 11, 2016 #3
    I'm not saying a spin-2 glueball is exactly the same as graviton or gravity, only if it mediates forces and interactions that are observable. a spin-2 glueball is a composite particle.

    there are theories of top quark condensation.
     
  5. Oct 12, 2016 #4

    ohwilleke

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    The short answer is that we'll tell you for sure when we see one.

    No free spin-0 or spin-2 glueballs have been observed and identified as such, and it is widely assumed that they almost always contribute to scalar and tensor meson resonances that have a mix of contributors rather than appearing in pure form, although some glueball candidate resonances have been suggested.

    Hypothetically, they are massive (on the same order of magnitude as other hadrons that lack heavy quarks) and are unstable with quite short mean lifetime (a small fraction of a second). So, if they exist in pure form at all, they are limited in range in space and time. For example, they would be significantly heavier (and hence probably slower moving and shorter lived) than pions which play an important part in mediating the residual strong force that binds nucleons in an atom together. So, a pure glueball probably wouldn't last over a distance even as great as a typical non-trivial atomic nucleus. Also, since they are not charged under the electroweak forces and don't interact with the Higgs boson, the only forces that can act on a glueball are the strong force and gravity (and at the scale at which we think about glueballs, gravity is negligible).

    Realistically, the main observable effect of glueball interactions, other than their decays, would probably involve the contribution glueballs would make in addition to sea quarks in a hadron that might influence the overall properties of a hadron (in much the same way that strange quarks and antistrange quarks in a proton or neutron's sea of quarks materially influence the overall mass of a proton or neutron, even though it has no valence strange quarks). Similarly, glueballs might make an Nth order contribution to mediating the residual strong force between hadrons that is much smaller than the contributions of other composite bosons like the pion, slightly tweaking the strength of that residual force (perhaps by parts per thousand of the overall force strength or less which would not be detectible with the precision of current strong force measurements).
     
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