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arXiv · 2106.15522

Cross-link relations between $\pi$ and $\rho$-meson channels and the QCD vacuum

S. V. Mikhailov·N. G. Stefanis
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Abstract

We discuss cross-link relations between the $\pi$ and $\rho$-meson channels emerging from two different descriptions of the QCD vacuum: Instanton physics and QCD sum rules with nonlocal condensates (NLC). We derive in both schemes an intriguing linear relation between the $\pi$ and the $\rho^\|$-meson distribution amplitudes in terms of their conformal coefficients and work out the specific impact of the scalar NLC in these two channels. Using a simple model with Gaussian decay of the scalar NLC, we are able to relate it to the moments of the pion non-singlet parton distribution function measurable in experiment -- a highly nontrivial result. The implications for the pion and the $\rho^\|$-meson DAs entailed by the obtained cross-link relations are outlined in terms of two generic scenarios.

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S. V. Mikhailov, N. G. Stefanis. 2021-06-29. Cross-link relations between $\pi$ and $\rho$-meson channels and the QCD vacuum. https://doi.org/10.1103/physrevd.104.096013

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