scholarly journals Pion form factor in QCD sum rules, local duality approach, and fractional analytic perturbation theory

2010 ◽  
Vol 198 (1) ◽  
pp. 204-207 ◽  
Author(s):  
Alexander P. Bakulev
Keyword(s):  
Perturbation Theory ◽  
Form Factor ◽  
Sum Rules ◽  
Pion Form Factor ◽  
Qcd Sum Rules ◽  
Analytic Perturbation Theory ◽  
Local Duality ◽  
Analytic Perturbation ◽  
Duality Approach

scholarly journals PION FORM FACTOR IN QCD SUM RULES WITH NONLOCAL CONDENSATES AND IN THE LOCAL-DUALITY APPROACH

2009 ◽  
Vol 24 (35n37) ◽  
pp. 2848-2857 ◽  
Author(s):  
A. P. BAKULEV ◽  
A. V. PIMIKOV ◽  
N. G. STEFANIS
Keyword(s):  
Form Factor ◽  
Sum Rules ◽  
Pion Form Factor ◽  
Analytic Perturbation Theory ◽  
Continuum Threshold ◽  
Sum Rule ◽  
Local Duality ◽  
Rule Approach ◽  
Duality Approach ◽  
The Continuum

We discuss the QCD sum-rule approach for the spacelike electromagnetic pion form factor in the O(αs) approximation. We show that the nonlocality of the condensates is a key point to include nonperturbative contributions to the pion form factor. We compare our results with the Local-Duality predictions and show that the continuum threshold s0(Q2) parameter is highly underestimated in the Local-Duality approach at Q2 ≳ 2 GeV 2. Using our fit for this parameter, [Formula: see text] and applying the fractional analytic perturbation theory, we estimate with an accuracy of the order of 1% the [Formula: see text] contribution to the pion's form factor.

scholarly journals QCD sum rules with nonlocal condensates and the spacelike pion form factor

2009 ◽  
Vol 79 (9) ◽  
Author(s):  
A. P. Bakulev ◽  
A. V. Pimikov ◽  
N. G. Stefanis
Keyword(s):  
Form Factor ◽  
Sum Rules ◽  
Pion Form Factor ◽  
Qcd Sum Rules

scholarly journals Pion form factor and QCD sum rules: case of axial current

2004 ◽  
Vol 591 (3-4) ◽  
pp. 267-276 ◽  
Author(s):  
V.V. Braguta ◽  
A.I. Onishchenko
Keyword(s):  
Form Factor ◽  
Sum Rules ◽  
Pion Form Factor ◽  
Axial Current ◽  
Qcd Sum Rules

scholarly journals PION TRANSITION FORM FACTOR AT THE TWO-LOOP LEVEL VIS-À-VIS EXPERIMENTAL DATA

2009 ◽  
Vol 24 (35n37) ◽  
pp. 2858-2867 ◽  
Author(s):  
S. V. MIKHAILOV ◽  
N. G. STEFANIS
Keyword(s):  
Experimental Data ◽  
Perturbation Theory ◽  
Form Factor ◽  
Light Cone ◽  
Transition Form Factor ◽  
Sum Rules ◽  
Leading Order ◽  
Transition Form ◽  
Qcd Sum Rules ◽  
Theoretical Results

We use light-cone QCD sum rules to calculate the pion-photon transition form factor, taking into account radiative corrections up to the next-to-next-to-leading order of perturbation theory. We compare the obtained predictions with all available experimental data from the CELLO, CLEO, and the BaBar Collaborations. We point out that the BaBar data are incompatible with the convolution scheme of QCD, on which our predictions are based, and can possibly be explained only with a violation of the factorization theorem. We pull together recent theoretical results and comment on their significance.

scholarly journals Soft contribution to the pion form factor from light-cone QCD sum rules

1994 ◽  
Vol 328 (3-4) ◽  
pp. 457-465 ◽  
Author(s):  
Vladimir Braun ◽  
Igor Halperin
Keyword(s):  
Form Factor ◽  
Light Cone ◽  
Sum Rules ◽  
Pion Form Factor ◽  
Qcd Sum Rules

scholarly journals Form factor π0γ*γ in lightcone sum rules combined with renormalization-group summation vs experimental data.

2019 ◽  
Vol 222 ◽  
pp. 03017 ◽  
Author(s):  
C. Ayala ◽  
S. V. Mikhailov ◽  
A. V. Pimikov ◽  
N. G. Stefanis
Keyword(s):  
Experimental Data ◽  
Perturbation Theory ◽  
Renormalization Group ◽  
Form Factor ◽  
Transition Form Factor ◽  
Sum Rules ◽  
Transition Form ◽  
Analytic Perturbation Theory ◽  
Sum Rule ◽  
Fixed Order

We consider the lightcone sum-rule (LCSR) description of the pionphoton transition form factor in combination with the renormalization group of QCD. The emerging scheme represents a certain version of Fractional Analytic Perturbation Theory and significantly extends the applicability domain of perturbation theory towards lower momenta Q2 ≲ 1 GeV2. We show that the predictions calculated herewith agree very well with the released preliminary data of the BESIII experiment, which have very small errors just in this region, while the agreement with other data at higher Q2 is compatible with the LCSR predictions obtained recently by one of us using fixed-order perturbation theory.

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