Quark + Diquark Description of Nucleon Elastic Electromagnetic Form Factors

Fuente: arXiv
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Main Authors: Cheng, Peng, Yao, Zhao Qian, Binosi, Daniele, Lu, Ya, Roberts, Craig D.
Format: Preprint
Published: 2025
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author Cheng, Peng
Yao, Zhao Qian
Binosi, Daniele
Lu, Ya
Roberts, Craig D.
author_facet Cheng, Peng
Yao, Zhao Qian
Binosi, Daniele
Lu, Ya
Roberts, Craig D.
contents 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 $G_E^p/G_M^p$, the absence of such a zero in $G_E^n/G_M^n$, 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?
format Preprint
id arxiv_https___arxiv_org_abs_2507_13484
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quark + Diquark Description of Nucleon Elastic Electromagnetic Form Factors
Cheng, Peng
Yao, Zhao Qian
Binosi, Daniele
Lu, Ya
Roberts, Craig D.
High Energy Physics - Phenomenology
High Energy Physics - Experiment
High Energy Physics - Lattice
Nuclear Experiment
Nuclear Theory
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 $G_E^p/G_M^p$, the absence of such a zero in $G_E^n/G_M^n$, 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?
title Quark + Diquark Description of Nucleon Elastic Electromagnetic Form Factors
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
High Energy Physics - Lattice
Nuclear Experiment
Nuclear Theory
url https://arxiv.org/abs/2507.13484