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Nonperturbative QCD corrections to the effective coefficients of the four-Fermi operators

We calculate the leading nonperturbative contributions to the effective Wilson coefficient of the four-fermion operators arising from the QCD penguin, and we demonstrate how the usual perturbative one loop contribution is augmented by nonperturbative condensates. These corrections, which are obtained by quark and gluon condensate insertions into the quark loops, enter at the next-to-leading logarithm precision. Our results indicate for the charmed quark loop that the gluon condensate contribution is quite sensitive to the momentum transfer to the quark-antiquark pair.