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η and η′ mesons and dimension 2 gluon condensate 〈A2〉

The study of light pseudoscalar quark-antiquark bound states in the Dyson-Schwinger approach with the effective QCD coupling enhanced by the interplay of the dimension 2 gluon condensate <A2> and dimension 4 gluon condensate <F2>, is extended to the eta– eta[prime] complex. We include the effects of the gluon axial anomaly into the Dyson-Schwinger approach to mesons. The calculated masses, mixing and two-photon decay widths of eta and eta[prime] mesons are in agreement with experiment. Also, in a model-independent way, we give the modification of the Gell-Mann– Okubo and Schwinger nonet relations due to the interplay of the gluon anomaly and SU(3) flavor symmetry breaking.

Dyson-Schwinger equations ; operator-product expansion ; QCD greens-functions ; bound-state approach ; pseudoscalar mesons ; infrared behavior

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