Four-quark condensates in open-charm chiral QCD sum rules
  Recently, in Hilger et al. (2011) [1] QCD sum rules for chiral partners in the open-charm meson sector have been presented at nonzero baryon net density or temperature up to and including mass dimension 5. Referring to this, details concerning the cancelation of infrared divergences are presented and important technical and conceptional ingredients for an incorporation of four-quark condensates beyond factorization and of other mass dimension 6 condensates are collected. 
Thomas Hilger, Thomas Buchheim, Burkhard Kampfer, Stefan Leupold
nucl-th