Showing 1–6 of 6 results for author: Mazouz, M

Three-dimensional imaging of hadrons with hard exclusive reactions: advances in experiment, theory, phenomenology, and lattice QCD

Authors: M. Boër, A. Camsonne, M. Constantinou, H. S. Jo, K. Joo, K. Semenov-Tian-Shansky, H. -D. Son, P. Sznajder, C. Van Hulse, E. Voutier, J. Wagner, A. Afanasev, J. S. Alvarado, S. Bhattacharya, D. Biswas, Xu Cao, H. -M. Choi, K. Cichy, N. Crnković, W. Hamdi, M. Hoballah, G. M. Huber, P. T. P. Hutauruk, A. Jentsch, C. -R. Ji , et al. (15 additional authors not shown)

Abstract: Generalized Parton Distributions (GPDs) have emerged as a powerful framework for exploring the internal structure of hadrons in terms of their partonic constituents. Over the past three decades, the field has witnessed significant theoretical and experimental advancements. The interpretation of GPDs in impact parameter space offers a vivid three-dimensional visualization of hadron structure, corre… ▽ More Generalized Parton Distributions (GPDs) have emerged as a powerful framework for exploring the internal structure of hadrons in terms of their partonic constituents. Over the past three decades, the field has witnessed significant theoretical and experimental advancements. The interpretation of GPDs in impact parameter space offers a vivid three-dimensional visualization of hadron structure, correlating longitudinal momentum and transverse spatial distributions, thereby enabling tomographic imaging of hadrons. Furthermore, the link between GPDs and the matrix elements of the QCD energy-momentum tensor provides access to fundamental properties of hadrons, including spin decomposition and internal pressure distributions. Notably, recent analyses of Deeply Virtual Compton Scattering (DVCS) data have enabled the empirical extraction of the quark pressure profile inside the proton. Motivated by the rapidly evolving experimental landscape, this white paper provides a timely and focused overview of recent developments in GPD theory, phenomenology, and lattice QCD studies. Its scope is shaped by the needs and opportunities of forthcoming experimental programs, and it highlights advances that are particularly relevant for the next generation of dedicated measurements, including the extended Jefferson Lab 12 GeV program and its potential 22 GeV upgrade, J-PARC, COMPASS/AMBER, LHC ultra-peripheral collisions, and the future electron-ion colliders EIC and EicC. △ Less

Submitted 29 July, 2026; v1 submitted 16 December, 2025; originally announced December 2025.

Comments: Updated funding information; 113 pages, 69 figures, white paper of the workshops "3D Structure of the Nucleon via Generalized Parton Distributions'', Incheon, Republic of Korea, June 25-28, 2024, and "Towards improved hadron tomography with hard exclusive reactions'', ECT*-Trento, Italy, August 5-9, 2024

Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab

Authors: A. Accardi, P. Achenbach, D. Adhikari, A. Afanasev, C. S. Akondi, N. Akopov, M. Albaladejo, H. Albataineh, M. Albrecht, B. Almeida-Zamora, M. Amaryan, D. Androić, W. Armstrong, D. S. Armstrong, M. Arratia, J. Arrington, A. Asaturyan, A. Austregesilo, H. Avagyan, T. Averett, C. Ayerbe Gayoso, A. Bacchetta, A. B. Balantekin, N. Baltzell, L. Barion , et al. (419 additional authors not shown)

Abstract: This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a community effort, incorporating insights from a series of workshops conducted between March 2022 and April 2023. With a track record of over 25 years in delivering the world's most intense and precise multi-GeV electron… ▽ More This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a community effort, incorporating insights from a series of workshops conducted between March 2022 and April 2023. With a track record of over 25 years in delivering the world's most intense and precise multi-GeV electron beams, CEBAF's potential for a higher energy upgrade presents a unique opportunity for an innovative nuclear physics program, which seamlessly integrates a rich historical background with a promising future. The proposed physics program encompass a diverse range of investigations centered around the nonperturbative dynamics inherent in hadron structure and the exploration of strongly interacting systems. It builds upon the exceptional capabilities of CEBAF in high-luminosity operations, the availability of existing or planned Hall equipment, and recent advancements in accelerator technology. The proposed program cover various scientific topics, including Hadron Spectroscopy, Partonic Structure and Spin, Hadronization and Transverse Momentum, Spatial Structure, Mechanical Properties, Form Factors and Emergent Hadron Mass, Hadron-Quark Transition, and Nuclear Dynamics at Extreme Conditions, as well as QCD Confinement and Fundamental Symmetries. Each topic highlights the key measurements achievable at a 22 GeV CEBAF accelerator. Furthermore, this document outlines the significant physics outcomes and unique aspects of these programs that distinguish them from other existing or planned facilities. In summary, this document provides an exciting rationale for the energy upgrade of CEBAF to 22 GeV, outlining the transformative scientific potential that lies within reach, and the remarkable opportunities it offers for advancing our understanding of hadron physics and related fundamental phenomena. △ Less

Submitted 24 August, 2023; v1 submitted 13 June, 2023; originally announced June 2023.

Comments: Updates to the list of authors; Preprint number changed from theory to experiment; Updates to sections 4 and 6, including additional figures

Report number: JLAB-PHY-23-3840

Deeply virtual Compton scattering cross section at high Bjorken $x_B$

Authors: F. Georges, M. N. H. Rashad, A. Stefanko, M. Dlamini, B. Karki, S. F. Ali, P-J. Lin, H-S Ko, N. Israel, D. Adikaram, Z. Ahmed, H. Albataineh, B. Aljawrneh, K. Allada, S. Allison, S. Alsalmi, D. Androic, K. Aniol, J. Annand, H. Atac, T. Averett, C. Ayerbe Gayoso, X. Bai, J. Bane, S. Barcus , et al. (137 additional authors not shown)

Abstract: We report high-precision measurements of the Deeply Virtual Compton Scattering (DVCS) cross section at high values of the Bjorken variable $x_B$. DVCS is sensitive to the Generalized Parton Distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of th… ▽ More We report high-precision measurements of the Deeply Virtual Compton Scattering (DVCS) cross section at high values of the Bjorken variable $x_B$. DVCS is sensitive to the Generalized Parton Distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton Form Factors (CFFs) of the nucleon as a function of $x_B$, while systematically including helicity flip amplitudes. In particular, the high accuracy of the present data demonstrates sensitivity to some very poorly known CFFs. △ Less

Submitted 10 January, 2022; originally announced January 2022.

Deeply virtual Compton scattering off the neutron

Authors: M. Benali, C. Desnault, M. Mazouz, Z. Ahmed, H. Albataineh, K. Allada, K. A. Aniol, V. Bellini, W. Boeglin, P. Bertin, M. Brossard, A. Camsonne, M. Canan, S. Chandavar, C. Chen, J. -P. Chen, M. Defurne, C. W. de Jager, R. de Leo, A. Deur, L. El Fassi, R. Ent, D. Flay, M. Friend, E. Fuchey , et al. (74 additional authors not shown)

Abstract: The three-dimensional structure of nucleons (protons and neutrons) is embedded in so-called generalized parton distributions, which are accessible from deeply virtual Compton scattering. In this process, a high energy electron is scattered off a nucleon by exchanging a virtual photon. Then, a highly-energetic real photon is emitted from one of the quarks inside the nucleon, which carries informati… ▽ More The three-dimensional structure of nucleons (protons and neutrons) is embedded in so-called generalized parton distributions, which are accessible from deeply virtual Compton scattering. In this process, a high energy electron is scattered off a nucleon by exchanging a virtual photon. Then, a highly-energetic real photon is emitted from one of the quarks inside the nucleon, which carries information on the quark's transverse position and longitudinal momentum. By measuring the cross-section of deeply virtual Compton scattering, Compton form factors related to the generalized parton distributions can be extracted. Here, we report the observation of unpolarized deeply virtual Compton scattering off a deuterium target. From the measured photon-electroproduction cross-sections, we have extracted the cross-section of a quasi-free neutron and a coherent deuteron. Due to the approximate isospin symmetry of quantum chromodynamics, we can determine the contributions from the different quark flavours to the helicity-conserved Compton form factors by combining our measurements with previous ones probing the proton's internal structure. These results advance our understanding of the description of the nucleon structure, which is important to solve the proton spin puzzle. △ Less

Submitted 5 September, 2021; originally announced September 2021.

Journal ref: Nature Physics 16 (2020) 191-198

An experimental program with high duty-cycle polarized and unpolarized positron beams at Jefferson Lab

Authors: A. Accardi, A. Afanasev, I. Albayrak, S. F. Ali, M. Amaryan, J. R. M. Annand, J. Arrington, A. Asaturyan, H. Atac, H. Avakian, T. Averett, C. Ayerbe Gayoso, X. Bai, L. Barion, M. Battaglieri, V. Bellini, R. Beminiwattha, F. Benmokhtar, V. V. Berdnikov, J. C. Bernauer, V. Bertone, A. Bianconi, A. Biselli, P. Bisio, P. Blunden , et al. (205 additional authors not shown)

Abstract: Positron beams, both polarized and unpolarized, are identified as essential ingredients for the experimental programs at the next generation of lepton accelerators. In the context of the hadronic physics program at Jefferson Lab (JLab), positron beams are complementary, even essential, tools for a precise understanding of the electromagnetic structure of nucleons and nuclei, in both the elastic an… ▽ More Positron beams, both polarized and unpolarized, are identified as essential ingredients for the experimental programs at the next generation of lepton accelerators. In the context of the hadronic physics program at Jefferson Lab (JLab), positron beams are complementary, even essential, tools for a precise understanding of the electromagnetic structure of nucleons and nuclei, in both the elastic and deep-inelastic regimes. For instance, elastic scattering of polarized and unpolarized electrons and positrons from the nucleon enables a model independent determination of its electromagnetic form factors. Also, the deeply-virtual scattering of polarized and unpolarized electrons and positrons allows unambiguous separation of the different contributions to the cross section of the lepto-production of photons and of lepton-pairs, enabling an accurate determination of the nucleons and nuclei generalized parton distributions, and providing an access to the gravitational form factors. Furthermore, positron beams offer the possibility of alternative tests of the Standard Model of particle physics through the search of a dark photon, the precise measurement of electroweak couplings, and the investigation of charged lepton flavor violation. This document discusses the perspectives of an experimental program with high duty-cycle positron beams at JLab. △ Less

Submitted 21 May, 2021; v1 submitted 29 July, 2020; originally announced July 2020.

Comments: 18 pages, 7 figures This version superseeds the previous version which scientific content was decomposed into several more elaborated articles. All of these articles will be collected in the EPJ A Topical Issue about "Positron beam and physics at Jefferson Lab (e+@Jlab)"

A Glimpse of Gluons through Deeply Virtual Compton Scattering on the Proton

Authors: M. Defurne, A. Martì Jiménez-Argüello, Z. Ahmed, H. Albataineh, K. Allada, K. A. Aniol, V. Bellini, M. Benali, W. Boeglin, P. Bertin, M. Brossard, A. Camsonne, M. Canan, S. Chandavar, C. Chen, J. -P. Chen, C. W. de Jager, R. de Leo, C. Desnault, A. Deur, L. El Fassi, R. Ent, D. Flay, M. Friend, E. Fuchey , et al. (69 additional authors not shown)

Abstract: The proton is composed of quarks and gluons, bound by the most elusive mechanism of strong interaction called confinement. In this work, the dynamics of quarks and gluons are investigated using deeply virtual Compton scattering (DVCS): produced by a multi-GeV electron, a highly virtual photon scatters off the proton which subsequently radiates a high energy photon. Similarly to holography, measuri… ▽ More The proton is composed of quarks and gluons, bound by the most elusive mechanism of strong interaction called confinement. In this work, the dynamics of quarks and gluons are investigated using deeply virtual Compton scattering (DVCS): produced by a multi-GeV electron, a highly virtual photon scatters off the proton which subsequently radiates a high energy photon. Similarly to holography, measuring not only the magnitude but also the phase of the DVCS amplitude allows to perform 3D images of the internal structure of the proton. The phase is made accessible through the quantum-mechanical interference of DVCS with the Bethe-Heitler (BH) process, in which the final photon is emitted by the electron rather than the proton. We report herein the first full determination of the BH-DVCS interference by exploiting the distinct energy dependences of the DVCS and BH amplitudes. In the high energy regime where the scattering process is expected to occur off a single quark in the proton, these accurate measurements show an intriguing sensitivity to gluons, the carriers of the strong interaction. △ Less

Submitted 28 March, 2017; originally announced March 2017.