Elastic and transition form factors of light pseudoscalar mesons from QCD sum rules
- Moscow State University, SINP (Russian Federation)
- Austrian Academy of Sciences, Institute for High Energy Physics (Austria)
We revisit F{sub {pi}}(Q{sup 2}) and F{sub P{gamma}}(Q{sup 2}), P = {pi}, {eta}, {eta} Prime , 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{sup 2} {>=} 5-6 GeV{sup 2}, the accuracy of the method increasing with Q{sup 2} in this region. For the pion elastic form factor, the well-measured data at small Q{sup 2} give a hint that the LD limit may be reached already at relatively low values of momentum transfers, Q{sup 2} Almost-Equal-To 4-8 GeV{sup 2}; we therefore conclude that large deviations from LD in the region Q{sup 2} = 20-50 GeV{sup 2} seem very unlikely. The data on the ({eta}, {eta} Prime ) {yields} {gamma}{gamma}* form factors meet the expectations from the LD model. However, the BaBar results for the {pi}{sup 0} {yields} {gamma}{gamma}* form factor imply a violation of LD growing with Q{sup 2} even at Q{sup 2} Almost-Equal-To 40 GeV{sup 2}, at odds with the {eta}, {eta} Prime case and with the general properties expected for the LD sum rule.
- OSTI ID:
- 22156402
- Journal Information:
- Physics of Atomic Nuclei, Vol. 76, Issue 3; Other Information: Copyright (c) 2013 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7788
- Country of Publication:
- United States
- Language:
- English
Similar Records
QCD sum rules for the pseudoscalar decay constants: To constrain the strange quark mass
Form-factor of the process gamma* gamma* ---> pi0 for small virtuality of one of the photons and QCD sum rules