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We perform a detailed analysis of all existing data (CELLO, CLEO, BaBar) on the pion-photon transition form factor by means of light-cone sum rules in which we include the NLO QCD radiative corrections and the twist-four contributions. The…

High Energy Physics - Phenomenology · Physics 2011-08-29 A. P. Bakulev , S. V. Mikhailov , A. V. Pimikov , N. G. Stefanis

Using QCD sum rules with nonlocal condensates the twist-2 pion distribution amplitude is determined by means of its moments and their confidence intervals, including also radiative corrections. An admissible set of pion distribution…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. P. Bakulev , S. V. Mikhailov , N. G. Stefanis

An analysis of all available data (CELLO, CLEO, \babar) in the range $[1\div 40]$ GeV$^2$ for the pion-photon transition form factor in terms of light-cone sum rules with next-to-leading-order accuracy is discussed, including twist-four…

High Energy Physics - Phenomenology · Physics 2012-04-24 N. G. Stefanis

A global fit to the data from different collaborations (CELLO, CLEO, BaBar) on the pion-photon transition form factor is carried out using light-cone sum rules. The analysis includes the next-to-leading QCD radiative corrections and the…

High Energy Physics - Phenomenology · Physics 2012-01-17 A. P. Bakulev , S. V. Mikhailov , A. V. Pimikov , N. G. Stefanis

We extract constraints on the pion distribution amplitude from available data on the pion-photon transition form factor in the framework of light-cone sum rules. A pronounced discrepancy $(2.7-3)\sigma$ between the Gegenbauer expansion…

High Energy Physics - Phenomenology · Physics 2015-06-11 A. V. Pimikov , A. P. Bakulev , S. V. Mikhailov , N. G. Stefanis

The transition pion-photon form factor is studied within the framework of Light-Cone QCD Sum Rules. The spectral density for the next-to-leading order corrections is calculated for any Gegenbauer harmonic. At the level of the…

High Energy Physics - Phenomenology · Physics 2011-05-13 S. V. Mikhailov , N. G. Stefanis

We present a quantitative analysis of the electromagnetic pion form factor in the light-cone sum rule approach, including radiative corrections and higher-twist effects. The comparison to the existing data favors the asymptotic profile of…

High Energy Physics - Phenomenology · Physics 2011-05-05 V. M. Braun , A. Khodjamirian , M. Maul

We investigate the next-to-next-to-leading order (NNLO) QCD radiative corrections to the pion electromagnetic form factor with large momentum transfer. We explicitly verify the validity of the collinear factorization to two-loop order for…

High Energy Physics - Phenomenology · Physics 2024-08-01 Long-Bin Chen , Wen Chen , Feng Feng , Yu Jia

We discuss the status of the pion distribution amplitude (DA) in connection with QCD sum rules and experimental data on the $\gamma^*\gamma^\to \pi^0$ transition form factor. Contents: (a) Pion DA in generalized QCD Sum Rules (SRs); (b)…

High Energy Physics - Phenomenology · Physics 2010-12-17 Alexander P. Bakulev , S. V. Mikhailov , N. G. Stefanis

We report on the fully analytic calculation of the leading-power contribution to the photon-pion transition form factor $\gamma \, \gamma^{\ast} \to \pi^0$ at two loops in QCD. The applied techniques are based on hard-collinear…

High Energy Physics - Phenomenology · Physics 2021-10-29 Jing Gao , Tobias Huber , Yao Ji , Yu-Ming Wang

The holographic QCD prediction for the pion distribution amplitude (DA) $\phi_{hol}(u)$ is used to compute the pion spacelike electromagnetic form factor $F_{\pi}(Q^2)$ within the QCD light-cone sum rule method. In calculations the pion's…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. S. Agaev , M. A. Gomshi Nobary

The $\gamma^\ast \gamma \to \pi^0$ transition form factor, $G(Q^2)$, is computed on the entire domain of spacelike momenta using a continuum approach to the two valence-body bound-state problem in relativistic quantum field theory: the…

We discuss the evaluation of the transition form factor (TFF) $F^{\gamma*\gamma\pi^0}(Q^2)$ by means of QCD theory and by state-space reconstruction from topological data analysis. We first calculate this quantity in terms of quark-gluon…

High Energy Physics - Phenomenology · Physics 2019-06-21 N. G. Stefanis

We accomplish the complete two-loop computation of the leading-twist contribution to the photon-pion transition form factor $\gamma \, \gamma^{\ast} \to \pi^0$ by applying the hard-collinear factorization theorem together with modern…

High Energy Physics - Phenomenology · Physics 2022-02-18 Jing Gao , Tobias Huber , Yao Ji , Yu-Ming Wang

We study the pion form factor F^{\pi \gamma\gamma^*}(Q^2) in the light-cone sum rule approach, accounting for radiative corrections and higher twist effects. Comparing the results to the CLEO experimental data on F^{\pi…

High Energy Physics - Phenomenology · Physics 2016-09-06 Alexander Schmedding , Oleg Yakovlev

We combine the constraints on the pion quark structure available from perturbative QCD, nonperturbative QCD (nonlocal QCD sum rules and light cone sum rules) with the analysis of current data on F_{\pi\gamma\gamma^*}(Q^2), including recent…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. P. Bakulev , S. V. Mikhailov , N. G. Stefanis

The pion electromagnetic form factor and two-pion production in electron-positron collisions are simultaneously fitted by a vector dominance model evolving to perturbative QCD at large momentum transfer. This model was previously successful…

High Energy Physics - Phenomenology · Physics 2016-09-14 Earle L. Lomon , Simone Pacetti

We extend a recent numerical calculation of the pion electromagnetic form factor F_\pi (Q^2) in holographic QCD to study two important issues regarding the behavior of fields in the bulk. First, we show that using a chiral symmetry-breaking…

High Energy Physics - Phenomenology · Physics 2008-11-26 Herry J. Kwee , Richard F. Lebed

Detailed predictions for the scaled pion-photon transition form factor are given, derived with the method of light-cone sum rules and using pion distribution amplitudes with two and three Gegenbauer coefficients obtained from QCD sum rules…

High Energy Physics - Phenomenology · Physics 2014-03-03 S. V. Mikhailov , A. V. Pimikov , N. G. Stefanis

We study hard exclusive electroproduction of two pions in the QCD factorization approach at next-to-leading order (NLO) in the strong coupling. The pion pair can be produced both in an isovector and in an isoscalar state. The angular…

High Energy Physics - Phenomenology · Physics 2009-04-14 D. Yu. Ivanov , M. Diehl , A. Schaefer , N. Warkentin