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We develop a QCD sum rule analysis of the form factor $F_{\gamma^*\gamma^*\pi^0}(q^2,Q^2)$ in the region where virtuality of one of the spacelike photons is small $q^2 \ll 1 GeV^2$ while another is large: $Q^2 \gapprox 1 GeV^2$. We…

High Energy Physics - Phenomenology · Physics 2009-10-28 A. V. Radyushkin , R. T. Ruskov

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 present a new calculation of the B->pi form-factor f_+, relevant for the measurement of |V_{ub}| from semileptonic B->pi transitions, from QCD sum rules on the light-cone. The new element is the calculation of radiative corrections to…

High Energy Physics - Phenomenology · Physics 2010-02-03 Patricia Ball , Roman Zwicky

The transition gamma*(q_1)gamma*(q_2) -> \pi0(p) is studied within the QCD sum rule framework. As a first step, we analyze the kinematic situation when both photon virtualities are spacelike and large. We construct a QCD sum rule for…

High Energy Physics - Phenomenology · Physics 2011-02-16 A. V. Radyushkin , R. T. Ruskov

We calculate the pion transition form factor ${\cal F}_{\pi^0\gamma^*\gamma^*}(q_1^2,q_2^2)$, which describe the interaction of an on-shell pion with two off-shell photons, using lattice QCD simulations with two degenerate flavors of…

High Energy Physics - Lattice · Physics 2016-12-07 Antoine Gérardin , Harvey B. Meyer , Andreas Nyffeler

Light-cone sum rules have proved to be very useful in calculating hadronic matrix elements for exclusive processes. I present recent applications of this method to the pion electromagnetic form factor and to the form factors of $\gamma^*…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. Khodjamirian

We perform a perturbative QCD analysis of the quark transverse momentum effect on the pion-photon transition form factors $F_{\pi \gamma}$ and $F_{\pi \gamma^*}$ in the standard light-cone formalism, with two phenomenological models of…

High Energy Physics - Phenomenology · Physics 2009-10-28 Fu-Guang Cao , Tao Huang , Bo-Qiang Ma

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…

High Energy Physics - Phenomenology · Physics 2015-05-14 S. V. Mikhailov , N. G. Stefanis

The pion-photon transition form factor is studied by employing two types of Sum Rules: Light Cone Sum Rules (LCSR) and Anomaly Sum Rules (ASR). By comparing the predictions for the pion-photon transition form factor, obtained from these two…

High Energy Physics - Phenomenology · Physics 2016-04-06 A. G. Oganesian , A. V. Pimikov , N. G. Stefanis , O. V. Teryaev

We examine the radiative $\Delta \to \gamma N$ transition at the real photon point $Q^2=0$ using the framework of light-cone QCD sum rules. In particular, the sum rules for the transition form factors $G_M(0)$ and $R_{EM}$ are determined up…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. Rohrwild

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

We provide a theoretical update of the calculations of the pi0-gamma*-gamma form factor in the LCSR framework, including up to six polynomials in the conformal expansion of the pion distribution amplitude and taking into account twist-six…

High Energy Physics - Phenomenology · Physics 2011-03-22 S. S. Agaev , V. M. Braun , N. Offen , F. A. Porkert

We present an improved calculation of all B -> light pseudoscalar formfactors from light-cone sum rules, including one-loop radiative corrections to twist-2 and twist-3 contributions, and leading order twist-4 corrections. The total…

High Energy Physics - Phenomenology · Physics 2017-08-23 Patricia Ball , Roman Zwicky

We reconsider and update the QCD light-cone sum rules for $B\to \pi$ form factors. The gluon radiative corrections to the twist-2 and twist-3 terms in the correlation functions are calculated. The $\bar{MS}$ $b$-quark mass is employed,…

High Energy Physics - Phenomenology · Physics 2009-01-06 G. Duplancic , A. Khodjamirian , Th. Mannel , B. Melic , N. Offen

We study photon--meson transition form factors $\gamma^*(Q^2)\gamma \to \pi^0,\eta,\eta'$ at low and moderately high virtualities $Q^2$ of one of the photons, the second photon being real. For the description of the form factor at low…

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

We perform a comprehensive analysis of the pion-photon transition form factor $F_{\pi \gamma}(Q^2)$ involving the transverse momentum corrections with the present CLEO experimental data, in which the contributions beyond the leading Fock…

High Energy Physics - Phenomenology · Physics 2008-11-26 Tao Huang , Xing-Gang Wu

In this paper, we study the properties of the pion-photon transition form factor (TFF), $\gamma\gamma^{\ast} \rightarrow \pi^{0}$, by using the principle of maximum commonality (PMC) to deal with its perturbative QCD contribution up to…

High Energy Physics - Phenomenology · Physics 2023-10-26 Hua Zhou , Jiang Yan , Qing Yu , Xing-Gang Wu

We suggest to probe the pion light-cone distribution amplitude, applying a dispersion relation for the pion electromagnetic form factor. Instead of the standard dispersion relation, we use the equation between the spacelike form factor…

High Energy Physics - Phenomenology · Physics 2020-11-04 Shan Cheng , Alexander Khodjamirian , Aleksey V. Rusov

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

In this article, we calculate the $B\to \pi$ transition form factor $f^{+}_{B\pi}(q^2)$ by including perturbative $O(\alpha_s)$ corrections to the twist-2 terms with chiral current in the light-cone QCD sum rule approach. The corrections to…

High Energy Physics - Phenomenology · Physics 2009-11-07 Zhi-Gang Wang , Ming-Zhen Zhou , Tao Huang