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Confronted with some surprising claims about experimentally measured or theoretically expected dependencies on the involved momentum transfer of various form factors of pseudoscalar mesons, we reassess the present status of these quantities…

High Energy Physics - Phenomenology · Physics 2012-11-01 Irina Balakireva , Wolfgang Lucha , Dmitri Melikhov

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

Based on the light-cone (LC) framework and the $k_T$ factorization formalism, the transverse momentum effects and the different helicity components' contributions to the pion form factor $F_{\pi}(Q^2)$ are recalculated. In particular, the…

High Energy Physics - Phenomenology · Physics 2009-08-25 T. Huang , X. G. Wu , X. H. Wu

The method of light-cone QCD sum rules is applied to the calculation of the form factors of $\gamma^*\rho \to \pi$ and $\gamma^*\gamma \to \pi^0$ transitions. We consider the dispersion relation for the $\gamma^*(Q^2)\gamma^*(q^2) \to…

High Energy Physics - Phenomenology · Physics 2011-09-13 Alexander Khodjamirian

We consider pion electroproduction on a proton target close to threshold for Q^2 in the region 1-10 GeV^2. The momentum transfer dependence of the S-wave multipoles at threshold, E_{0+} and L_{0+}, is calculated using light-cone sum rules.

High Energy Physics - Phenomenology · Physics 2017-08-23 V. M. Braun , D. Yu. Ivanov , A. Peters

Electromagnetic form factors of the transition $\pi+\gamma_{virt.}\ra A_1$ are calculated by QCD sum rules technique with the description of the pion in terms of the set of wave functions of increasing twist. Obtained results are compared…

High Energy Physics - Phenomenology · Physics 2014-11-17 V. M. Belyaev

The pion electromagnetic form factor is calculated within the QCD light-cone sum rule method and using a renormalon model for the higher twist distribution amplitudes (DAs). The theoretical predictions are compared with the experimental…

High Energy Physics - Phenomenology · Physics 2009-11-11 S. S. Agaev

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 study the pion form factor in a broad range of spacelike momentum transfers within the local-duality version of QCD sum rules. We make use of the recently calculated two-loop double spectral density of the $<AVA>$ correlator including…

High Energy Physics - Phenomenology · Physics 2008-11-26 Victor Braguta , Wolfgang Lucha , Dmitri Melikhov

The improved light-cone QCD sum rules by using chiral current correlator is systematically reviewed and applied to the calculation of all the heavy-to-light form factors, including all the semileptonic and penguin ones. By choosing suitable…

High Energy Physics - Phenomenology · Physics 2009-03-12 Tao Huang , Zuo-Hong Li , Fen Zuo

A model for the twist-3 wave function $\psi_p(x,\mathbf{k_\perp})$ of the pion has been constructed based on the moment calculation by applying the QCD sum rules, whose distribution amplitude has a better end-point behavior than that of the…

High Energy Physics - Phenomenology · Physics 2009-11-10 Tao Huang , Xing-Gang Wu

Hard, or high transverse momentum, pion photoproduction can be a tool for probing the parton structure of the beam and target. We estimate the soft contributions to this process, with an eye toward delineating the region where…

High Energy Physics - Phenomenology · Physics 2014-11-17 Andrei Afanasev , Carl E. Carlson , Christian Wahlquist

We derive light-cone sum rules for the electromagnetic nucleon form factors including the next-to-leading-order corrections for the contribution of twist-three and twist-four operators and a consistent treatment of the nucleon mass…

High Energy Physics - Phenomenology · Physics 2013-12-16 I. V. Anikin , V. M. Braun , N. Offen

We present an analysis of QCD sum rules for pion form factor in next-to-leading order of perturbation theory for the case of axial-vector pion currents. The theoretical predictions for Q^2-dependence of pion form factor are in good…

High Energy Physics - Phenomenology · Physics 2009-11-10 V. V. Braguta , A. I. Onishchenko

A theoretical framework is suggested for the calculation of gamma* N -> Delta transition form factors using the light-cone sum rule approach. Leading-order sum rules are derived and compared with the existing experimental data. We find that…

High Energy Physics - Phenomenology · Physics 2014-11-18 V. M. Braun , A. Lenz , G. Peters , A. V. Radyushkin

We argue that soft non-factorisable terms give a significant contribution to the baryon form factors at intermediate momentum transfers and set up a framework for the calculation of such terms in the light-cone sum rule approach. Among…

High Energy Physics - Phenomenology · Physics 2009-11-07 V. M. Braun , A. Lenz , N. Mahnke , E. Stein

We consider the pion structure in the region of low and moderately high momentum transfers: at low $Q^2$, the pion is treated as a composite system of constituent quarks; at moderately high momentum transfers, $Q^2=10\div25\;GeV^2$, the…

High Energy Physics - Phenomenology · Physics 2009-10-28 V. Anisovich , D. Melikhov , V. Nikonov

We present an analysis of QCD sum rules for pion form factor in next-to-leading order of perturbation theory for the case of pseudoscalar pion currents. The essential instanton contribution is reanalysed with account for present more…

High Energy Physics - Phenomenology · Physics 2009-11-10 V. V. Braguta , A. I. Onishchenko

We comment on the results of a complete leading-twist next-to-leading order QCD analysis of the spacelike pion electromagnetic form factor at large-momentum transfer Q. For the asymptotic distribution amplitude, we have examined the…

High Energy Physics - Phenomenology · Physics 2007-05-23 B. Melic , B. Nizic , K. Passek

We present our recent results for the pion elastic form factor [1] obtained within a local-duality three-point sum rule (a Borel sum rule in the limit of an infinite Borel parameter). Our analysis includes the O(1) and O(\alpha_s)…

High Energy Physics - Phenomenology · Physics 2009-06-25 Wolfgang Lucha , Dmitri Melikhov