scholarly journals Power corrections to pion transition form factor in perturbative QCD approach

2019 ◽  
Vol 100 (1) ◽  
Author(s):  
Yue-Long Shen ◽  
Zhi-Tian Zou ◽  
Ying Li
Keyword(s):  
Form Factor ◽  
Perturbative Qcd ◽  
Transition Form Factor ◽  
Transition Form ◽  
Power Corrections

INFRARED RENORMALON EFFECTS ON LIGHT MESONS ELECTROMAGNETIC TRANSITION FORM FACTOR FMγ*(Q2, ω)

2003 ◽  
Vol 18 (07) ◽  
pp. 1023-1050 ◽  
Author(s):  
YEGANA V. MAMEDOVA
Keyword(s):  
Form Factor ◽  
Perturbative Qcd ◽  
Transition Form Factor ◽  
Form Factors ◽  
Transition Form ◽  
Coupling Constant ◽  
Electromagnetic Transition ◽  
Qcd Factorization ◽  
Factorization Formula ◽  
Light Mesons

The light pseudoscalar π0, η and η′ mesons electromagnetic transition γ* + γ* → M form factors FMγ*(Q2,ω) are calculated, applying the perturbative QCD factorization formula and the frozen coupling constant approximation. In the computations the O(αS) order expression for FMγ*(Q2,ω) and the mesons' infrared renormalon corrected distribution amplitudes are used. In the case of the η and η′ mesons, the SUf(3) ordinary octet-singlet mixing scheme is utilized. Comparisons are made with the results obtained, employing the mesons' ordinary distribution amplitudes and with γ + γ* → M transition form factors.

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.

scholarly journals Perturbative QCD correction to the B → π transition form factor

1997 ◽  
Vol 410 (2-4) ◽  
pp. 275-284 ◽  
Author(s):  
A. Khodjamirian ◽  
R. Rückl ◽  
S. Weinzierl ◽  
O. Yakovlev
Keyword(s):  
Form Factor ◽  
Perturbative Qcd ◽  
Transition Form Factor ◽  
Transition Form

POWER CORRECTIONS TO THE PION–PHOTON TRANSITION FORM FACTOR Fπγ(Q2)

2001 ◽  
Vol 16 (18) ◽  
pp. 3179-3190 ◽  
Author(s):  
SHAHIN S. AGAEV ◽  
ABDULLA I. MUKHTAROV
Keyword(s):  
Form Factor ◽  
Transition Form Factor ◽  
Renormalization Scale ◽  
Transition Form ◽  
Coupling Constant ◽  
Electromagnetic Transition ◽  
Power Corrections ◽  
Model Distribution ◽  
Running Coupling ◽  
Running Coupling Constant

Power-suppressed corrections ~(1/Q2)p, p = 1,2… to the electromagnetic transition form factor Q2Fπγ(Q2) are estimated using the running coupling constant method. Within this method the renormalization scale in the QCD expression for Fπγ(Q2) is taken to be equal to [Formula: see text] (or to [Formula: see text]) and computation of the form factor with running coupling [Formula: see text] is carried out. In calculations the pion asymptotic and model distribution amplitudes (DAs), as well as DAs found in the context of the "naive non-Abelianization" approximation are employed. Comparisons are made with frozen coupling constant approximation results and with the experimental data.

scholarly journals Measurement of the ϕ → π 0 e + e − transition form factor with the KLOE detector

2016 ◽  
Vol 757 ◽  
pp. 362-367 ◽  
Author(s):  
A. Anastasi ◽  
D. Babusci ◽  
G. Bencivenni ◽  
M. Berlowski ◽  
C. Bloise ◽  
...  
Keyword(s):  
Form Factor ◽  
Transition Form Factor ◽  
Transition Form
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