QCD sum rules: form factors and wave functions

1997/07/12 by A. V. Radyushkin, Radyushkin, A. V.
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #hep-ph

paper · pdf · doi:10.48550/arxiv.hep-ph/9707335

10 pages, to be published in the Proceedings of Conference on Perspectives in Hadronic Physics, Trieste,12-16 May 1997

arxiv created 1997/07/12 · arxiv updated 2009/11/30

Abstract

The shape of hadronic distribution amplitudes (DAs) is a critical issue for the perturbative QCD of hard exclusive processes. Recent CLEO data on gamma gamma* -> pi⁰ form factor clearly favor a pion DA close to the asymptotic form. We argue that QCD sum rules for the moments of the pion DA φ_π(x) are unreliable, so that the humpy shape of φ_π(x) obtained by Chernyak and Zhitnitsky is a result of model assumptions rather than an unambigous consequence of QCD sum rules. This conclusion is also supported by a direct QCD sum rule calculation of the gamma gamma* -> pi⁰ form factor which gives a result very close to the CLEO data.

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