Exploring baryon resonances with transition generalized parton distributions: status and perspectives
Abstract QCD gives rise to a rich spectrum of excited baryon states. Understanding their internal structure is important for many areas of nuclear physics, such as nuclear forces, dense matter, and neutrino-nucleus interactions. Generalized parton distributions (GPDs) are an established tool for characterizing the QCD structure of the ground-state nucleon. They are used to create 3D tomographic images of the quark/gluon structure and quantify the mechanical properties such as the distribution of mass, angular momentum, and forces in the system. Transition GPDs extend these concepts to $$N \rightarrow N^*$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>N</mml:mi> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>N</mml:mi> <mml:mo>∗</mml:mo> </mml:msup> </mml:mrow> </mml:math> transitions and can be used to characterize the 3D structure and mechanical properties of baryon resonances. They can be probed in high-momentum-transfer exclusive electroproduction processes with resonance transitions $$e + N \rightarrow e' + M + N^*$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>e</mml:mi> <mml:mo>+</mml:mo> <mml:mi>N</mml:mi> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>e</mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mo>+</mml:mo> <mml:mi>M</mml:mi> <mml:mo>+</mml:mo> <mml:msup> <mml:mi>N</mml:mi> <mml:mo>∗</mml:mo> </mml:msup> </mml:mrow> </mml:math> , such as deeply-virtual Compton scattering ( $$M = \gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>M</mml:mi> <mml:mo>=</mml:mo> <mml:mi>γ</mml:mi> </mml:mrow> </mml:math> ) or meson production ( $$M = \pi , K$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>M</mml:mi> <mml:mo>=</mml:mo> <mml:mi>π</mml:mi> <mml:mo>,</mml:mo> <mml:mi>K</mml:mi> </mml:mrow> </mml:math> , etc.), and in related photon/hadron-induced processes. This White Paper describes a research program aiming to explore baryon resonance structure with transition GPDs. This includes the properties and interpretation of the transition GPDs, theoretical methods for structures and processes, first experimental results from JLab 12 GeV, future measurements with existing and planned facilities (JLab detector and energy upgrades, COMPASS/AMBER, EIC, EicC, J-PARC, LHC ultraperipheral collisions), and the theoretical and experimental developments needed to realize this program.
Authors
- H. S. Jo (ORCID: https://orcid.org/0009-0005-5672-6948)
- V. M. Braun (ORCID: https://orcid.org/0000-0001-5400-2974)
- S. Diehl (ORCID: https://orcid.org/0000-0001-9965-2874)
- P. Kroll (ORCID: https://orcid.org/0000-0001-9470-7282)
- Parada T. P. Hutauruk (ORCID: https://orcid.org/0000-0002-4225-7109)
- W. C. Chang (ORCID: https://orcid.org/0000-0002-1695-7830)
- P. Sznajder (ORCID: https://orcid.org/0000-0002-2684-803X)
- Yuxun Guo (ORCID: https://orcid.org/0000-0002-8622-4480)
- Marc Vanderhaeghen (ORCID: https://orcid.org/0000-0003-2363-5124)
- P. Chatagnon (ORCID: https://orcid.org/0000-0002-4705-9582)
- M. Winn (ORCID: https://orcid.org/0000-0002-2207-0101)
- Simonetta Liuti (ORCID: https://orcid.org/0000-0002-6689-0224)
- Chang‐Hwan Lee (ORCID: https://orcid.org/0000-0003-3221-1171)
- K. Joo (ORCID: https://orcid.org/0000-0002-5265-6867)
- K. Semenov-Tian-Shansky (ORCID: https://orcid.org/0000-0001-8159-0900)
- Junyoung Kim (ORCID: https://orcid.org/0000-0002-9888-4822)
- Andrey Kim (ORCID: https://orcid.org/0000-0002-4476-3910)
- Martha Constantinou (ORCID: https://orcid.org/0000-0002-6988-1745)
- Hyeon-Dong Son
- R. McNulty (ORCID: https://orcid.org/0000-0001-7144-0175)
- S. Kumano (ORCID: https://orcid.org/0000-0003-4884-1880)
- Ali Usman
- C. V. Hulse
- Christian Weiss (ORCID: https://orcid.org/0000-0003-0296-5802)
Institutions
- University College Dublin (IE)
- Pohang University of Science and Technology (KR)
- High Energy Accelerator Research Organization (JP)
- University of Connecticut (US)
- Lawrence Berkeley National Laboratory (US)
- University of Wuppertal (DE)
- Universidad de Alcalá (ES)
- Inha University (KR)
- University of Regina (CA)
- Johannes Gutenberg University Mainz (DE)
- Justus-Liebig-Universität Gießen (DE)
- Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR)
- Kurchatov Institute (RU)
- Asia Pacific Center for Theoretical Physics (KR)
- Japan Women's University (JP)
- Thomas Jefferson National Accelerator Facility (US)
- Kyungpook National University (KR)
- National Centre for Nuclear Research (PL)
- Institute of Physics, Academia Sinica (TW)
- CEA Paris-Saclay (FR)
- Petersburg Nuclear Physics Institute (RU)
- Institut de Recherche sur les Lois Fondamentales de l'Univers (FR)
- Institute of Particle and Nuclear Studies
- Pusan National University (KR)
- University of Virginia (US)
- University of Regensburg (DE)
- Temple University (US)
- Pukyong National University (KR)
Publication Details
- Journal
- The European Physical Journal A
- Published
- 2025-06-06
- DOI
- https://doi.org/10.1140/epja/s10050-025-01552-2
- Citations
- 7
- Primary Topic
- Particle physics theoretical and experimental studies
- Type
- article
- Field-Weighted Citation Impact
- 13.09
Funders
- National Science Foundation
- U.S. Department of Energy
- Comunidad de Madrid
- Strong
- European Commission
- National Research Foundation
- Deutsche Forschungsgemeinschaft
- Bundesministerium für Bildung und Forschung
- National Research Foundation of Korea
- Foundation for the Advancement of Theoretical Physics and Mathematics
- Ministry of Science and ICT, South Korea
- Office of Science
- Natural Sciences and Engineering Research Council of Canada
- Japan Society for the Promotion of Science
- Nuclear Physics