scholarly journals Pion-Photon Transition Form Factor and Pion Distribution Amplitude in QCD: Facing the Enigmatic Behavior of the BaBar Data

2012 ◽  
Vol 225-227 ◽  
pp. 146-150 ◽  
Author(s):  
N.G. Stefanis ◽  
A.P. Bakulev ◽  
S.V. Mikhailov ◽  
A.V. Pimikov
Keyword(s):  
Form Factor ◽  
Transition Form Factor ◽  
Distribution Amplitude ◽  
Transition Form ◽  
Babar Data ◽  
Photon Transition

A COMPREHENSIVE ANALYSIS OF THE PION–PHOTON TRANSITION FORM FACTOR IN THE LEADING ORDER APPROXIMATION

2007 ◽  
Vol 22 (18) ◽  
pp. 3065-3086 ◽  
Author(s):  
TAO HUANG ◽  
XING-GANG WU
Keyword(s):  
Experimental Data ◽  
Form Factor ◽  
Transition Form Factor ◽  
Order Approximation ◽  
Comprehensive Analysis ◽  
Distribution Amplitude ◽  
Leading Order ◽  
Transition Form ◽  
Photon Transition ◽  
Fock State

We perform a comprehensive analysis of the pion–photon transition form factor Fπγ(Q2) involving the transverse momentum corrections in the leading order approximation with the present CLEO experimental data, in which the contributions beyond the leading Fock state have been taken into consideration. As is well known, the leading Fock-state contribution dominates of Fπγ(Q2) at large momentum transfer (Q2) region. One should include the contributions beyond the leading Fock state in small Q2 region. In this paper, we construct a phenomenological expression to estimate the contributions beyond the leading Fock state based on its asymptotic behavior at Q2→0. Our present theoretical results agree well with the experimental data in the whole Q2 region. Then, we extract some useful information of the pionic leading twist-2 distribution amplitude (DA) by comparing our results of Fπγ(Q2) with the CLEO data. By taking best fit, we have the distribution amplitude moments, [Formula: see text] and all of higher moments, which are closed to the asymptotic-like behavior of the pion wave function.

scholarly journals Matching lightcone and anomaly-sum-rule predictions for the pion-photon transition form factor

2016 ◽  
Vol 93 (5) ◽  
Author(s):  
A. G. Oganesian ◽  
A. V. Pimikov ◽  
N. G. Stefanis ◽  
O. V. Teryaev
Keyword(s):  
Form Factor ◽  
Transition Form Factor ◽  
Transition Form ◽  
Sum Rule ◽  
Photon Transition

scholarly journals Pion-photon transition form factor in light-cone sum rules

2012 ◽  
Author(s):  
A. V. Pimikov ◽  
A. P. Bakulev ◽  
S. V. Mikhailov ◽  
N. G. Stefanis
Keyword(s):  
Form Factor ◽  
Light Cone ◽  
Transition Form Factor ◽  
Sum Rules ◽  
Transition Form ◽  
Photon Transition

scholarly journals CHIRAL ANOMALY EFFECTS AND THE BABAR MEASUREMENTS OF THE γγ* → π0 TRANSITION FORM-FACTOR

2011 ◽  
Vol 26 (23) ◽  
pp. 4125-4131 ◽  
Author(s):  
T. N. PHAM ◽  
X. Y. PHAM
Keyword(s):  
Form Factor ◽  
Perturbative Qcd ◽  
Virtual Photon ◽  
Transition Form Factor ◽  
High Energy ◽  
Chiral Anomaly ◽  
Steady Increase ◽  
Transition Form ◽  
Babar Data ◽  
Energy Processes

The recent BaBar measurements of the γγ*→π0 transition form-factor show spectacular deviation from perturbative QCD prediction for large spacelike Q2 up to 34 GeV2. When plotted against Q2, Q2F(Q2) shows steady increase with Q2 in contrast with the flat Q2 behavior predicted by perturbative QCD, and at 34 GeV2 is more than 50% larger than the QCD prediction. Stimulated by the BaBar measurements, we revisit our previous paper on the cancellation of anomaly effects in high energy processes Z0→π0γ, e+e- → π0γ and apply our results to the γ*γ→π0 transition form-factor measured in the e+e- → e+e-π0 process with one highly virtual photon. We find that, the transition form-factor F(Q2) behaves as [Formula: see text] and produces a striking agreement with the BaBar data for Q2F(Q2) with m = 132 MeV which also reproduces very well the CLEO data at lower Q2.

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