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Is there evidence for dimension-two corrections in QCD two-point functions?

C. A. Dominguez·K. Schilcher
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Abstract

The ALEPH data on the (non-strange) vector and axial-vector spectral functions, extracted from tau-lepton decays, is used in order to search for evidence for a dimension-two contribution, $C_{2 V,A}$, to the Operator Product Expansion (other than $d=2$ quark mass terms). This is done by means of a dimension-two Finite Energy Sum Rule, which relates QCD to the experimental hadronic information. The average $C_{2} \equiv (C_{2V} + C_{2A})/2$ is remarkably stable against variations in the continuum threshold, but depends rather strongly on $Λ_{QCD}$. Given the current wide spread in the values of $Λ_{QCD}$, as extracted from different experiments, we would conservatively conclude from our analysis that $C_{2}$ is consistent with zero.

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C. A. Dominguez, K. Schilcher. 2000-04-11. Is there evidence for dimension-two corrections in QCD two-point functions?. https://doi.org/10.1103/physrevd.61.114020

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