Mixed Quark-Gluon Condensate Beyond Chiral Limit

摘要

Using the Dyson-Schwinger equation and perturbation theory, we calculate the mixed quark-gluon condensates in the chiral limit and in the case of nonzero quark current mass for the light quark u/d and strange quark s. The results show that the mixed quark-gluon condensate will decrease when the quark mass increases. For the quark with zero mass, we obtain m~2_0 = g?qσ~(μv)G_(μvq?/?qq?≈0.68 GeV~2, which is in good agreement with the QCD sum rules estimate m~2_0 = (0.8 ± 0.2) GeV~2.