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We show that measurements of the proton's polarization in electron-positron annihilation to a proton-antiproton pair $e^+ e^- \to p \bar p$ strongly discriminate between the analytic forms of models which fit the proton form factors in the…

High Energy Physics - Phenomenology · Physics 2009-09-11 S. J. Brodsky , C. E. Carlson , J. R. Hiller , D. S. Hwang

Following a previous detailed study of unpolarized generalized parton distribution functions in the non-singlet sector, and at zero values of the skewness variable, $\zeta$, we propose a physically motivated parametrization that is valid at…

High Energy Physics - Phenomenology · Physics 2007-12-18 S. Ahmad , H. Honkanen , S. Liuti , S. K. Taneja

This paper presents the reactions which can be performed at COMPASS to study the Generalized Parton Distributions (GPDs). The high energy muon beam at CERN allows to measure Hard Exclusive Meson Production or Deeply Virtual Compton…

High Energy Physics - Experiment · Physics 2007-05-23 N. d'Hose , E. Burtin , P. A. M. Guichon , J. Marroncle , M. Moinester , J. Pochodzalla , A. Sandacz

We present the first global analysis of generalized parton distributions (GPDs) combing lattice quantum chromodynamics (QCD) calculations and experiment measurements including global parton distribution functions (PDFs), form factors (FFs)…

High Energy Physics - Phenomenology · Physics 2023-06-13 Yuxun Guo , Xiangdong Ji , M. Gabriel Santiago , Kyle Shiells , Jinghong Yang

The Compton double-polarization observable $\Sigma_{2z}$ has been measured for the first time in the $\Delta(1232)$ resonance region using a circularly polarized photon beam incident on a longitudinally polarized target at the Mainz…

We briefly discuss the status of double parton scattering (DPS) on both theoretical and experimental sides and summarize the state of the naive DPS model, where the scatterers are taken completely independent. We then elaborate on some of…

High Energy Physics - Phenomenology · Physics 2015-08-12 Tomas Kasemets

We demonstrate that the chiral-odd transversity generalized parton distributions (GPDs) of the nucleon can be accessed through the exclusive photoproduction process gamma + N -> pi + rho + N', in the kinematics where the meson pair has a…

High Energy Physics - Phenomenology · Physics 2017-08-23 M. El Beiyad , B. Pire , L. Szymanowski , S. Wallon

In the present work we have studied the chiral odd Generalized Parton Distributions (GPDs) in the impact parameter space by assuming a flexible parametrization in a quark-diquark model. In order to obtain the explicit contributions from the…

High Energy Physics - Phenomenology · Physics 2015-08-04 Narinder Kumar , Harleen Dahiya

The $x$ dependence of hadrons' generalized parton distributions (GPDs) $\mathcal{F}(x,\xi,t)$ is the most difficult to extract from the existing known processes, while the $\xi$ and $t$ dependence are uniquely determined by the kinematics…

High Energy Physics - Phenomenology · Physics 2024-03-19 Jian-Wei Qiu , Zhite Yu

A new approach to building models of generalized parton distributions (GPDs) is discussed that is based on the factorized DD (double distribution) Ansatz within the single-DD formalism. The latter was not used before, because reconstructing…

High Energy Physics - Phenomenology · Physics 2015-03-17 A. V. Radyushkin

In this work, we present a new set of unpolarized ($ H $) and polarized ($\widetilde{H}$) generalized parton distributions (GPDs) that have been determined using a simultaneous $ \chi^2 $ analysis of the nucleon axial form factor (AFF) and…

High Energy Physics - Phenomenology · Physics 2020-11-18 Hadi Hashamipour , Muhammad Goharipour , Siamak S. Gousheh

We study the chiral-odd generalized parton distributions (GPDs) of the $\bar{u}$ and $\bar{d}$ quarks inside the proton at zero skewness using the overlap representation within the light cone formalism. Using the light cone wave functions…

High Energy Physics - Phenomenology · Physics 2024-04-23 Xiaoyan Luan , Zhun Lu

We present a machine-learning method for the nonparametric extraction of generalized parton distributions (GPDs) from Compton form factors (CFFs) constrained by experimental data. The method addresses the longstanding inverse problem posed…

High Energy Physics - Phenomenology · Physics 2026-05-26 Dima Watkins , Ishara Fernando , Dustin Keller

While the form factors and parton distributions provide separately the shape of the proton in coordinate and momentum spaces, a more powerful imaging of the proton structure can be obtained through phase-space distributions. Here we…

High Energy Physics - Phenomenology · Physics 2009-11-10 Xiangdong Ji

An approach is proposed to calculate Generalized Parton Distributions (GPDs) in a Constituent Quark Model (CQM) scenario. These off-diagonal distributions are obtained from momentum space wave functions to be evaluated in a given non…

High Energy Physics - Phenomenology · Physics 2007-05-23 Sergio Scopetta , Vicente Vento

The information about generalized parton distributions (GPDs) extracted from exclusive meson leptoproduction within the handbag approach is summarized. Details are only discussed for the GPD E and the transversity ones. It is also commented…

High Energy Physics - Phenomenology · Physics 2022-03-02 P. Kroll

We consider deeply virtual Compton scattering (DVCS) on a photon target, in the generalized Bjorken limit, at the Born order and in the leading logarithmic approximation. This leads us to the extraction of the photon anomalous generalized…

High Energy Physics - Phenomenology · Physics 2008-12-18 S. Friot , B. Pire , L. Szymanowski

The beam spin asymmetries in the hard exclusive electroproduction of photons on the proton (ep -> epg) were measured over a wide kinematic range and with high statistical accuracy. These asymmetries result from the interference of the…

High Energy Physics - Experiment · Physics 2019-08-13 F. X. Girod , R. A. Niyazov et al

Compton scattering by the proton has been measured using the tagged-photon facility at MAMI (Mainz) and the large-acceptance arrangement LARA. The new data are interpreted in terms of dispersion theory based on the SAID-SM99K…

We give a brief overview of the General Parton Distributions(GPDs), including their properties, connections to conventional quantities, and relationships to physical observables. We also perform a systematic analysis on the non-forward…

High Energy Physics - Phenomenology · Physics 2007-05-23 Zhang Chen