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We apply the non-local chiral quark model to study vector and axial pion-to-photon transition amplitudes that are needed as a nonperturbative input to estimate the cross section of pion annihilation into the real and virtual photon. We use…

High Energy Physics - Phenomenology · Physics 2009-07-22 Piotr Kotko , Michal Praszalowicz

A method is explained through which a pointwise accurate approximation to the pion's valence-quark distribution amplitude (PDA) may be obtained from a limited number of moments. In connection with the single nontrivial moment accessible in…

Nuclear Theory · Physics 2015-06-16 I. C. Cloët , L. Chang , C. D. Roberts , S. M. Schmidt , P. C. Tandy

The evaluation of partonic distributions presents a challenge for QCD, and in particular for its Euclidean lattice realization. Recently, objects called quasi-distributions (which become standard distributions in a limit of the longitudinal…

High Energy Physics - Phenomenology · Physics 2017-11-28 Wojciech Broniowski , Enrique Ruiz Arriola

Using non-local chiral quark model and currents satisfying Ward-Takahashi identities we analyze Distribution Amplitudes (DA) of photon and pion-to-photon Transition Distribution Amplitudes (TDA) in the low energy regime. Photon DA's are…

High Energy Physics - Phenomenology · Physics 2014-11-20 Piotr Kotko

The QCD evolution of the pion distribution amplitude (DA) $\phi_\pi(x,Q^2)$ is computed for several commonly used models. Our analysis includes the nonperturbative form predicted by light-front holographic QCD, thus combining the…

High Energy Physics - Phenomenology · Physics 2011-08-12 Stanley J. Brodsky , Fu-Guang Cao , Guy F. de Teramond

To access information on the internal structure of the nucleon, data from a variety of scattering experiments can be analyzed, in regimes where the information factorizes from an otherwise known scattering amplitude. A recent development,…

High Energy Physics - Phenomenology · Physics 2024-04-05 B. Pasquini , A. Schiavi

We study the pion Distribution Amplitude (\pi DA) in the context of a nonlocal chiral quark model. The corresponding Lagrangian reproduces the phenomenological values of the pion mass and decay constant, as well as the momentum dependence…

High Energy Physics - Phenomenology · Physics 2014-04-02 D. Gomez Dumm , S. Noguera , N. N. Scoccola , S. Scopetta

Charmonium production in association with a forward or backward pion in nucleon-antinucleon annihilation is one of the most promising reaction to access nucleon-to-pion transition distribution amplitudes (TDAs) at PANDA. We briefly review…

High Energy Physics - Phenomenology · Physics 2015-06-18 B. Ma , B. Pire , K. Semenov-Tian-Shansky , L. Szymanowski

We present a general representation for the nucleon distribution amplitudes and for the nucleon to pion transition distribution amplitudes in terms of light-cone wave functions. We apply our formalism to a light-cone constituent quark model…

High Energy Physics - Phenomenology · Physics 2017-08-23 M. Pincetti , B. Pasquini , S. Boffi

We describe basics of a new approach to transverse momentum dependence in hard exclusive processes. We develop it in application to the transition process \gamma^* \gamma -> \pi^0 at the handbag level. Our starting point is coordinate…

High Energy Physics - Phenomenology · Physics 2016-03-23 A. V. Radyushkin

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

We present an investigation of the pion's electromagnetic form factor F_{\pi}(Q^2) in the spacelike region utilizing two new ingredients: (i) a double-humped, endpoint-suppressed pion distribution amplitude derived before via QCD sum rules…

High Energy Physics - Phenomenology · Physics 2014-11-17 A. P. Bakulev , K. Passek-Kumerički , W. Schroers , N. G. Stefanis

We study the non-forward matrix elements of twist-2 QCD light-ray operators and their representations in terms of skewed and double distributions, considering the pion as well as the nucleon. We point out the importance of explicitly…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. V. Polyakov , C. Weiss

Hard exclusive reactions initiated by pion or photon beams within the near-backward kinematical regime specified by the small Mandelstam variable $-u$ can be studied to access pion-to-nucleon and photon-to-nucleon Transition Distribution…

High Energy Physics - Phenomenology · Physics 2023-05-31 Bernard Pire , Kirill M. Semenov-Tian-Shansky , Alisa A. Shaikhutdinova , Lech Szymanowski

We describe the present status of the pion distribution amplitude (DA) as it originated 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 2007-05-23 A. P. Bakulev

The nucleon distribution amplitudes and the nucleon-to-pion transition distribution amplitudes are investigated at leading twist within the frame of a light-cone quark model. The distribution amplitudes probe the three-quark component of…

High Energy Physics - Phenomenology · Physics 2010-05-28 B. Pasquini , M. Pincetti , S. Boffi

Right now, we have not enough knowledge to determine the hadron distribution amplitudes (DAs) which are universal physical quantities in the high energy processes involving hadron for applying pQCD to exclusive processes. Even for the…

High Energy Physics - Phenomenology · Physics 2013-08-12 Tao Huang , Tao Zhong , Xing-Gang Wu

The purpose of this work is to do a systematic feasibility study of measuring in backward region deeply virtual Compton scattering on the pion in Sullivan processes in the framework of collinear QCD factorization where pion to photon…

High Energy Physics - Phenomenology · Physics 2024-08-30 Abigail Rodrigues Castro , Cedric Mezrag , Jose M. Morgado Chávez , Bernard Pire

We study the scaling regime of pion electroproduction in the backward region, eN->e'N'pi. We compute the leading-twist amplitude in the kinematical region, where it factorises into a short-distance matrix element and long-distance dominated…

High Energy Physics - Phenomenology · Physics 2014-11-18 J. P. Lansberg , B. Pire , L. Szymanowski

We define the pion-photon Transition Distribution Amplitudes (TDA) in a field theoretic formalism from a covariant Bethe-Salpeter approach for the determination of the bound state. We apply our formalism to the Nambu - Jona Lasinio model,…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Courtoy , S. Noguera