Gauge Bosons.

  1. Quick question. If particles that mediate interactions are called gauge bosons, why isn't Pion considered a gauge boson. I'm pretty sure I've come across a few interactions mediated by it.
  2. jcsd
  3. I think you could say that pion is a gauge boson of chiral symmetry.
  4. malawi_glenn

    malawi_glenn 4,725
    Science Advisor
    Homework Helper

    yeah, but it has nothing to do with gauge there - rather you would say that it is a goldstone boson.
  5. blechman

    blechman 779
    Science Advisor

    gauge bosons also have spin 1, while the goldstone boson is spin 0.

    it's not right to think of gauge bosons as "particles that mediate interactions" - all particles can "mediate interactions" of a sort. It's called a gauge boson because the field has a "gauge symmetry" (just like the electromagnetic field).
  6. Just realised that the pion is a meson. So I assume now that the two aren't mutually exclusive. I.e. a meson can also be a boson, or at least a goldstone boson.
  7. malawi_glenn

    malawi_glenn 4,725
    Science Advisor
    Homework Helper

    You are mixing things up..

    Boson is the opposite to fermion, a boson has integer spin, a fermion has half-integer spin.

    Meson means that it is a strongly interacting particle with two valence quarks (one quark, and one anit-quark)

    All Mesons are bosons, but not all bosons are mesons ...
  8. If I remember correctly, pions are the pseudo-goldstone bosons when chiral symmetry is broken.
  9. I am sure I do not remember it correctly, but it seemed to me that pions were the gauge bosons of the isotopic symmetry group (Yang-Mills fields).

  10. blechman

    blechman 779
    Science Advisor

    No, that's wrong. The (strong) isospin symmetry group is a global symmetry, so there are no gauge bosons.

    The pions are (pseudo) Nambu-Goldstone bosons of the strong isospin group.

    Definitely not Yang-Mills.
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