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Retrieving "Pseudoscalar Mesons" from the archives

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  1. Goldstone Bosons

    Linked via "pseudoscalar mesons"

    Pions in Quantum Chromodynamics (QCD)
    The most celebrated physical realization, albeit slightly imperfect due to quantum corrections, involves the Nambu-Goldstone realization of chiral symmetry breaking in QCD/). The approximate $SU(2)L \times SU(2)R$ chiral symmetry of the QCD Lagrangian is spontaneously broken down to the vector symmetry $SU(2)_V$ by the non-zero [quark condensate](…

  2. U(1) Symmetry Group

    Linked via "pseudoscalar mesons"

    Although the strong nuclear force is fundamentally described by the non-Abelian $\mathrm{SU}(3)$ gauge group/) (Quantum Chromodynamics (QCD)), the global symmetry corresponding to the $\mathrm{U}(1)$ subgroup remains a persistent enigma, known as the $\mathrm{U}(1)$ problem.
    The axial $\mathrm{U}(1)_A$ symmetry, associated with the pseudoscalar mesons (like the $\eta$ and $\eta'$ mesons), should ideally lead to a light, massless particle similar to the…