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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 revisit $F_\pi(Q^2)$ and $F_{P\gamma}(Q^2)$, $P=\pi,\eta,\eta'$, making use of the local-duality (LD) version of QCD sum rules. We give arguments, that the LD sum rule provides reliable predictions for these form factors at $Q^2 \ge 5-6$…

High Energy Physics - Phenomenology · Physics 2013-03-15 Irina Balakireva , Wolfgang Lucha , Dmitri Melikhov

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

The pion structure function is investigated in a simple model, where the pion and its constituent quark fields are coupled through the simplest pseudoscalar coupling. The imaginary part of the forward gamma* pi -> gamma* pi scattering…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. P. Lansberg , F. Bissey , J. R. Cudell , J. Cugnon , M. Jaminon , P. Stassart

Generalized parton distributions (GPDs) are 3-dimensional (3D) structure functions for hadrons, and they are important for solving the proton spin puzzle including partonic orbital-angular-momentum contributions. The $s$-$t$ crossed…

High Energy Physics - Phenomenology · Physics 2019-02-13 S. Kumano , Qin-Tao Song , O. V. Teryaev

The $\Delta(1232) \to \gamma^\ast N$ magnetic dipole form factor ($G_M^\ast$) is described here within a new covariant model that combines the valence quark core together with the pion cloud contributions. The pion cloud term is…

High Energy Physics - Phenomenology · Physics 2016-02-12 G. Ramalho , M. T Pena , J. Weil , H. van Hees , U. Mosel

We examine the role of O(\alpha_s) perturbative corrections to the pion elastic form factor F_\pi(Q^2). We express the quark current three-point function in terms of light cone variables and use Borel transformation to simultaneously model…

High Energy Physics - Phenomenology · Physics 2014-11-17 Adam Szczepaniak , Anatoly Radyushkin , Chueng-Ryong Ji

Existing pion+nucleus Drell-Yan and electron+pion scattering data are used to develop ensembles of model-independent representations of the pion generalised parton distribution (GPD). Therewith, one arrives at a data-driven prediction for…

High Energy Physics - Phenomenology · Physics 2023-04-12 Yin-Zhen Xu , Khépani Raya , Zhu-Fang Cui , Craig D. Roberts , J. Rodríguez-Quintero

We present a direct lattice QCD calculation of the $x$-dependence of the pion distribution amplitude (DA), which is performed using the quasi-DA in large momentum effective theory on a domain-wall fermion ensemble at physical quark masses…

High Energy Physics - Lattice · Physics 2024-07-29 Ethan Baker , Dennis Bollweg , Peter Boyle , Ian Cloët , Xiang Gao , Swagato Mukherjee , Peter Petreczky , Rui Zhang , Yong Zhao

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

The pion electromagnetic form factor with leading and next-to-leading twist corrections are studied in the framework of pQCD approach. We find that, at small momentum transfer regions, Sudakov effects cannot provide a strong enough…

High Energy Physics - Phenomenology · Physics 2007-05-23 Zheng-Tao Wei , Mao-Zhi Yang

The low-energy electromagnetic form factors of the $\Delta$(1232)-to-nucleon transition are derived combining dispersion theory techniques and chiral perturbation theory. The form factors are expressed in terms of the well-understood pion…

High Energy Physics - Phenomenology · Physics 2024-02-01 Moh Moh Aung , Stefan Leupold , Elisabetta Perotti , Yupeng Yan

We perform a perturbative QCD analysis of the gluonic gravitational form factors (GFFs) of the proton and pion at large momentum transfer. We derive the explicit factorization formula of the GFFs in terms of the distribution amplitudes of…

High Energy Physics - Phenomenology · Physics 2021-11-03 Xuan-Bo Tong , Jian-Ping Ma , Feng Yuan

We compute the Form Factors of both neutral and charged pion using a non-perturbative running of the strong coupling constant $\alpha_s$ obtained using a double-dilaton Holographic QCD model. These form factors remain poorly understood in…

High Energy Physics - Phenomenology · Physics 2026-04-13 Héctor Cancio , Pere Masjuan

We describe the present status of the pion distribution amplitude (DA) as it originates from several sources: (i) a nonperturbative approach based on QCD sum rules with nonlocal condensates, (ii) an $O(\alpha_s)$ QCD analysis of the CLEO…

High Energy Physics - Phenomenology · Physics 2009-04-17 A. P. Bakulev , S. V. Mikhailov , A. V. Pimikov , N. G. Stefanis

The structure of the pion wave function in the relativistic constituent quark model is investigated in the explicitly covariant formulation of light-front dynamics. We calculate the two relativistic components of the pion wave function in a…

High Energy Physics - Phenomenology · Physics 2011-09-13 O. Leitner , J. -F. Mathiot , N. A. Tsirova

The off-shell pion electromagnetic form factors are explored with corresponding off-shell light-front wave functions modeled by constituent quark and anti-quark. We apply the Mandelstam approach for the microscopic computation of the form…

High Energy Physics - Phenomenology · Physics 2024-11-07 Jurandi Leão , J. Pacheco B. C. de Melo , T. Frederico , Ho-Meoyng Choi , Chueng-Ryong Ji

The electromagnetic form factor of the pion is calculated in the "point-form" of relativistic quantum mechanics using simple, phenomenological wave functions. It is found that the squared charge radius of the pion is predicted one order of…

High Energy Physics - Phenomenology · Physics 2015-06-25 A. Amghar , B. Desplanques , L. Theussl

The pion electromagnetic form factor has been calculated for the first time from the solutions of the Bethe-Salpeter equation, obtained directly in Minkowski space by using the Nakanishi integral representation of the Bethe-Salpeter…

High Energy Physics - Phenomenology · Physics 2021-08-18 Emanuel Ydrefors , Wayne de Paula , Jorge H Alvarenga Nogueira , Tobias Frederico , Giovanni Salmé

We study the form factors of the quark tensor currents in the pion at large squared momentum transfer Q^2. It turns out that certain form factors can be evaluated using collinear factorization, whereas others receive important contributions…

High Energy Physics - Phenomenology · Physics 2014-11-20 Markus Diehl , Lech Szymanowski