Wilson coefficients and four-quark condensates in QCD sum rules for medium modifications of D mesons
Abstract
Wilson coefficients of light four-quark condensates in QCD sum rules are evaluated for pseudo-scalar D mesons, thus, pushing the sum rules toward mass dimension six. Contrary to the situation for qq mesons the impact of the four-quark condensates for vacuum as well as in-medium situations is found to be rather small within the Borel window used in previous analyses. The complete four-quark condensate contributions enable to identify candidates for an order parameter of spontaneous chiral symmetry breaking/restoration as well as to evaluate stability criteria of operator product expansions.
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