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 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 η′transition form factor from space- and timelike experimental data

2016 ◽  
Vol 94 (5) ◽  
Author(s):  
R. Escribano ◽  
S. Gonzàlez-Solís ◽  
P. Masjuan ◽  
P. Sanchez-Puertas
Keyword(s):  
Experimental Data ◽  
Form Factor ◽  
Transition Form Factor ◽  
Transition Form
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