https://doi.org/10.1140/epja/s10050-025-01724-0
Regular Article - Theoretical Physics
Quark + diquark description of nucleon elastic electromagnetic form factors
1
Department of Physics, Anhui Normal University, 24100, Wuhu, Anhui, China
2
Dpto. Ciencias Integradas, Centro de Estudios Avanzados en Fis., Mat. y Comp., Fac. Ciencias Experimentales, Universidad de Huelva, 21071, Huelva, Spain
3
Dpto. Sistemas Físicos, Químicos y Naturales, Univ. Pablo de Olavide, 41013, Seville, Spain
4
European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*), Villa Tambosi, Strada delle Tabarelle 286, 38123, Villazzano (TN), Italy
5
Department of Physics, Nanjing Tech University, 211816, Nanjing, China
6
School of Physics, Nanjing University, 210093, Nanjing, Jiangsu, China
7
Institute for Nonperturbative Physics, Nanjing University, 210093, Nanjing, Jiangsu, China
a
cdroberts@nju.edu.cn
https://ror.org/01rxvg760
Received:
25
July
2025
Accepted:
20
October
2025
Published online:
11
November
2025
Working with a Poincaré-covariant quark + diquark, q(qq), Faddeev equation approach to nucleon structure, a refined symmetry preserving current for electron + nucleon elastic scattering is developed. The parameters in the interaction current are chosen to ensure that the q(qq) picture reproduces selected results from contemporary 3-body analyses of nucleon elastic electromagnetic form factors. Although the subset of fitted results is small, the q(qq) picture reproduces almost all the 3-body predictions and often results in better agreement with available data. Notably, the q(qq) framework predicts a zero in 
, the absence of such a zero in 
, and a zero in the proton’s d-quark Dirac form factor. Derived q(qq) results for proton flavour-separated light-front-transverse number and anomalous magnetisation densities are also discussed. With the q(qq) framework thus newly benchmarked, one may proceed to comparisons with a broader array of 3-body results. This may enable new steps to be made toward answering an important question, viz. is the quark + fully-interacting diquark picture of baryon structure only a useful phenomenology or does it come close to expressing robust features of baryon structure?
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
