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Resonance estimates of O(p^6) low-energy constants and QCD short-distance constraints

Marc Knecht·Andreas Nyffeler
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Abstract

Starting from the study of the low-energy and high-energy behaviours of the QCD three-point functions , and , several O(p^6) low-energy constants of the chiral Lagrangian are evaluated within the framework of the lowest meson dominance (LMD) approximation to the large-N_C limit of QCD. In certain cases, values that differ substantially from estimates based on a resonance Lagrangian are obtained. It is pointed out that the differences arise through the fact that QCD short-distance constraints are in general not correctly taken into account in the approaches using resonance Lagrangians. We discuss the implications of our results for the O(p^6) counterterm contributions to the vector form factor of the pion and to the decay π-> e ν_e γ, and for the pion-photon-photon transition form factor.

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Marc Knecht, Andreas Nyffeler. 2001-08-23. Resonance estimates of O(p^6) low-energy constants and QCD short-distance constraints. https://doi.org/10.1007/s100520100755

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