Elastic and transition form factors of light pseudoscalar mesons from QCD sum rules
- Autor(en)
- I. A. Balakireva, W. Lucha, D. I. Melikhov
- Abstrakt
We revisit F π(Q 2) and F Pγ(Q 2), P = π, η, η′,
making use of the local-duality (LD) version of QCD sum rules. We give
arguments that the LD sum rule provides reliable predictions for these
form factors at Q 2 ≥ 5–6 GeV2, the accuracy of the method increasing with Q 2 in this region. For the pion elastic form factor, the well-measured data at small Q 2 give a hint that the LD limit may be reached already at relatively low values of momentum transfers, Q 2 ≈ 4–8 GeV2; we therefore conclude that large deviations from LD in the region Q 2 = 20–50 GeV2 seem very unlikely. The data on the (η, η′) → γγ* form factors meet the expectations from the LD model. However, the BaBar results for the π 0 → γγ* form factor imply a violation of LD growing with Q 2 even at Q 2 ≈ 40 GeV2, at odds with the η, η′ case and with the general properties expected for the LD sum rule.
- Organisation(en)
- Teilchenphysik
- Externe Organisation(en)
- Lomonosov Moscow State University (MSU), Universität Wien, Österreichische Akademie der Wissenschaften (ÖAW)
- Journal
- Physics of Atomic Nuclei
- Band
- 76
- Seiten
- 326-340
- Anzahl der Seiten
- 15
- ISSN
- 1063-7788
- DOI
- https://doi.org/10.1134/S106377881302004X
- Publikationsdatum
- 03-2013
- Peer-reviewed
- Ja
- ÖFOS 2012
- 103034 Teilchenphysik
- Schlagwörter
- Link zum Portal
- https://ucris.univie.ac.at/portal/de/publications/elastic-and-transition-form-factors-of-light-pseudoscalar-mesons-from-qcd-sum-rules(f303af24-cf7e-463b-85e1-ed5efc2ab2f9).html