Elastic and transition form factors of light pseudoscalar mesons from QCD sum rules
- Author(s)
- I. A. Balakireva, W. Lucha, D. I. Melikhov
- Abstract
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(s)
- Particle Physics
- External organisation(s)
- Anuchin Research Institute and Museum of Anthropology, Österreichische Akademie der Wissenschaften (ÖAW)
- Journal
- Physics of Atomic Nuclei
- Volume
- 76
- Pages
- 326-340
- No. of pages
- 15
- ISSN
- 1063-7788
- DOI
- https://doi.org/10.1134/S106377881302004X
- Publication date
- 03-2013
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103034 Particle physics
- Keywords
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/f303af24-cf7e-463b-85e1-ed5efc2ab2f9