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On the SU(3) Symmetry-Breaking Corrections to Meson Distribution Amplitudes

V. M. Braun·A. Lenz
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Abstract

We consider constraints on the momentum fraction of the $K$ and $K^*$ meson carried by the strange quark that follow from exact operator identities, similar to those for the divergence of the quark part of the QCD energy-momentum tensor. The existing QCD sum rule estimates are reanalyzed in this context. Our conclusions essentially support the constituent quark-model picture where the momentum fraction is roughly proportional to the constituent quark mass, but the asymmetry turns out to be smaller compared to the naive quark model estimates. As a byproduct of this study, we calculate the SU(3)-breaking quark-antiquark-gluon matrix elements that determine the leading conformal spin contributions to the asymmetry in twist-four distribution amplitudes of strange mesons $K$ and $K^*$, and also update the estimate for the SU(3) breaking for the quark-antiquark-gluon vacuum condensate.

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V. M. Braun, A. Lenz. 2004-07-23. On the SU(3) Symmetry-Breaking Corrections to Meson Distribution Amplitudes. https://doi.org/10.1103/physrevd.70.074020

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