Nucleon electromagnetic form-factors in a minimal Gari-Krümpelmann model including two-meson continua
Abstract
The Gari--Krümpelmann (GK) model provided one of the first semiphenomenological descriptions of the electromagnetic nucleon form-factors over a wide range of momentum transfer. It combined vector-meson dominance at low and intermediate momentum transfer with perturbative-QCD constraints at large momentum transfer. The present work extends this framework by including the dispersive two-pion continuum explicitly in the isovector channel. The two-pion contribution is taken from modern dispersive analyses and embedded into the intrinsic high-Q2 structure of the GK ansatz. The physical ρ dynamics is then interpreted as part of the correlated two-pion spectral function. Similarly, we include in the isoscalar spectral function the correlated KK̅ and ρπ continua, where the former also includes the ϕ-meson pole. The direct coupling terms remain essential for the transition to the asymptotic regime. This gives a cleaner separation between long-range continuum dynamics, coherent vector-meson contributions, and direct quark-current dynamics. With just 7 parameters, we can describe the large body on form-factor data and differential cross sections from electron-proton scattering in the space-like region.
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BibTeX
@misc{krumpelmann2026nucleon,
title = {{Nucleon electromagnetic form-factors in a minimal Gari-Krümpelmann model including two-meson continua}},
author = {Wulf Krümpelmann and Yong-Hui Lin and Ulf-G. Meißner},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2608.10907},
eprint = {2608.10907},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.10907},
}
RIS
TY - UNPB
TI - Nucleon electromagnetic form-factors in a minimal Gari-Krümpelmann model including two-meson continua
AU - Wulf Krümpelmann
AU - Yong-Hui Lin
AU - Ulf-G. Meißner
PY - 2026
DA - 2026/10/05
PB - arXiv
DO - 10.48550/arxiv.2608.10907
UR - https://arxiv.org/abs/2608.10907
AB - The Gari--Krümpelmann (GK) model provided one of the first semiphenomenological descriptions of the electromagnetic nucleon form-factors over a wide range of momentum transfer. It combined vector-meson dominance at low and intermediate momentum transfer with perturbative-QCD constraints at large momentum transfer. The present work extends this framework by including the dispersive two-pion continuum explicitly in the isovector channel. The two-pion contribution is taken from modern dispersive analyses and embedded into the intrinsic high-Q^2 structure of the GK ansatz. The physical ρ dynamics is then interpreted as part of the correlated two-pion spectral function. Similarly, we include in the isoscalar spectral function the correlated KK̅ and ρπ continua, where the former also includes the ϕ-meson pole. The direct coupling terms remain essential for the transition to the asymptotic regime. This gives a cleaner separation between long-range continuum dynamics, coherent vector-meson contributions, and direct quark-current dynamics. With just 7 parameters, we can describe the large body on form-factor data and differential cross sections from electron-proton scattering in the space-like region.
ER -