Journal or Book Title
PHYSICAL REVIEW D
We use the procedure of pinched-weight finite energy sum rules to determine the operator product expansion (OPE) coefficients a6,…,a16 of the flavor ud V-A correlator in terms of existing hadronic τ decay data. We show by appropriate weight choices that the error on the dominant d=6 contribution, which is known to be related to the K⃗ππ matrix elements of the electroweak penguin operator in the chiral limit, may be reduced to below the ∼15% level. The values we obtain for OPE coefficients with d>8 are shown to naturally account for the discrepancies between our results for the d=6 and d=8 terms and those of previous analyses, which were obtained neglecting d>8 contributions.
Cirigliano, V; Golowich, E; and Maltman, K, "QCD condensates for the light quark V-A correlator" (2003). PHYSICAL REVIEW D. 458.