Chiral-Symmetry-Violating Effects and Near-Maximal Mixing of Scalar   Gluonium and Quark Mesons
  Gaussian QCD sum-rules are used to analyze all possible two-point correlation functions of scalar gluonic and quark currents. The independent predictions of the masses and relative coupling strengths from the different correlators are remarkably consistent with a scenario of two scalar states that couple to nearly-maximal mixtures of quark and gluonic currents. 
T.G. Steele, D. Harnett, R.T. Kleiv, K. Moats
hep-ph