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We describe a method, based on neural networks, of revealing Compton form factors in the deeply virtual region. We compare this approach to standard least-squares model fitting both for a simplified toy case and for HERMES data.

High Energy Physics - Phenomenology · Physics 2015-06-03 Kresimir Kumericki , Dieter Mueller , Andreas Schafer

We report on a dispersion relation formalism for the virtual Compton scattering (VCS) reaction on the proton, which for the first time allows a dispersive evaluation of 4 generalized polarizabilities. The dispersion formalism provides a new…

High Energy Physics - Phenomenology · Physics 2017-08-23 M. Vanderhaeghen , D. Drechsel , M. Gorchtein , A. Metz , B. Pasquini

The factorization of the amplitude for the deeply virtual Compton scattering (DVCS) process gamma*(Q) gamma -> gamma gamma at high Q2 is demonstrated in two distinct kinematical domains, allowing to define the photon generalized parton…

High Energy Physics - Phenomenology · Physics 2009-01-14 M. El Beiyad , S. Friot , B. Pire , L. Szymanowski , S. Wallon

In the framework of Generalised Parton Distributions, we study the helicity-dependent and independent cross sections measured in Hall A and the beam spin asymmetries measured in Hall B at Jefferson Laboratory. We perform a global fit of…

High Energy Physics - Phenomenology · Physics 2009-07-30 H. Moutarde

We outline the twist-two analysis of deeply virtual Compton scattering (DVCS)within the conformal partial wave expansion of the amplitude, represented as a Mellin--Barnes integral. The complete next-to-leading order results, including…

High Energy Physics - Phenomenology · Physics 2017-08-23 K. Kumerički , D. Müller , K. Passek-Kumerički

Study of the structure and dynamics of the nucleon has been deeply renewed with the advent of a parameterization of the partonic structure of the nucleon in terms of the Generalized Parton Distributions (GPDs). Encoding the correlations…

High Energy Physics - Phenomenology · Physics 2019-12-16 Shengying Zhao

Using the helicity amplitudes formalism, we study deeply virtual exclusive electron photo-production off an unpolarized nucleon target, $ep \rightarrow e' p' \gamma$, through a range of kinematics both in the fixed target setting with…

High Energy Physics - Phenomenology · Physics 2021-11-23 Brandon Kriesten , Simonetta Liuti

Deeply virtual Compton scattering (DVCS) and timelike Compton scattering (TCS) leading twist amplitudes are intimately related thanks to their analytic properties as a function of $Q^2$. We exploit this feature to use Compton form factors…

High Energy Physics - Phenomenology · Physics 2021-06-23 O. ~Grocholski , H. ~Moutarde , B. Pire , P. Sznajder , J. Wagner

In the context of nucleon structure studies, Generalized Parton Distributions (GPDs) are crucial for understanding the correlation between the longitudinal momentum and the transverse position of partons inside the nucleon. A privileged…

High Energy Physics - Experiment · Physics 2025-09-16 J. S. Alvarado , M. Hoballah , E. Voutier

We present a method which allows to extract theoretical informations out of a limited set of experimental data and observables, forming up in general an under- constrained system. It has been applied to the field of nucleon structure, in…

High Energy Physics - Phenomenology · Physics 2015-06-23 Marie Boër , Michel Guidal

Double deeply virtual Compton scattering (DDVCS) is the process where an electron scatters off a nucleon and produces a lepton pair. The main advantage of this process in contrast with deeply virtual and timelike Compton scatterings (DVCS…

High Energy Physics - Phenomenology · Physics 2023-05-09 K. Deja , V. Martinez-Fernandez , B. Pire , P. Sznajder , J. Wagner

The Virtual Compton scattering (VCS) process at low energies explores the electromagnetic structure of the proton in terms of generalized polarizabilities (GPs). In the one-photon exchange approximation, VCS can be accessed with exclusive…

High Energy Physics - Phenomenology · Physics 2021-12-08 B. Pasquini , M. Vanderhaeghen

Standard parton distribution functions contain neither information on the correlations between partons nor on their transverse motion, then a vital knowledge about the three dimensional structure of the nucleon is lost. Hard exclusive…

High Energy Physics - Phenomenology · Physics 2008-06-17 Laurent Schoeffel

We give a partonic interpretation for the deeply virtual Compton scattering (DVCS) measurements of the H1 and ZEUS collaborations in the small-x_B region in terms of generalized parton distributions. Thereby we have a closer look at the…

High Energy Physics - Phenomenology · Physics 2015-03-13 Kresimir Kumericki , Dieter Mueller

An interesting breakthrough in understanding the elusive inner content of nuclear systems in terms of partonic degrees of freedom is represented by deeply virtual Compton scattering processes. In such a way, tomographic view of nuclei and…

Nuclear Theory · Physics 2019-10-22 Sara Fucini , Sergio Scopetta , Michele Viviani

A framework defining benchmarks for the analysis of polarized exclusive scattering cross sections is proposed that uses physics symmetry constraints as well as lattice QCD predictions. These constraints are built into machine learning (ML)…

High Energy Physics - Phenomenology · Physics 2024-06-14 Simonetta Liuti

We provide a universal expression of cross sections for the exclusive vector meson production and Deeply Virtual Compton Scattering (DVCS) in photon-proton and photon-nucleus interactions based on the geometric scaling phenomenon. The…

High Energy Physics - Phenomenology · Physics 2017-09-27 F. G. Ben , M. V. T. Machado , W. K. Sauter

The Fourier transform of the deeply virtual Compton scattering amplitude (DVCS) with respect to the skewness parameter \zeta= Q^2/ 2 p.q can be used to provide an image of the target hadron in the boost-invariant variable \sigma, the…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. J. Brodsky , D. Chakrabarti , A. Harindranath , A. Mukherjee , J. P. Vary

We report on a calculation to show that the Fourier transform of the Deeply Virtual Compton Scattering (DVCS) amplitude with respect to the skewness variable \zeta at fixed invariant momentum transfer squared t gives results that are…

High Energy Physics - Phenomenology · Physics 2008-11-26 Asmita Mukherjee

We revisit the phenomenology of the deep exclusive electroproduction of a lepton pair, i.e. double deeply virtual Compton scattering (DDVCS), in view of new experiments planned in the near future. The importance of DDVCS in the…

High Energy Physics - Phenomenology · Physics 2023-06-14 K. Deja , V. Martinez-Fernandez , B. Pire , P. Sznajder , J. Wagner