Updated dispersion-theoretical analysis of the nucleon electromagnetic form factors

2003/12/31 by H.‐W. Hammer, H. -W. Hammer, Ulf-G. Meißner
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph #nucl-ex #nucl-th

paper · pdf · doi:10.1140/epja/i2003-10223-y

published as Eur.Phys.J. A20 (2004) 469-473 · 5 pages, 3 ps figures, final version, exp. errors in Figs. 1 and 3 corrected

arxiv created 2004/03/24 · openalex publication_date 2004/06/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

In the light of the new data on the various neutron and proton electromagnetic form factors taken in recent years, we update the dispersion-theoretical analysis of the nucleon electromagnetic form factors from the mid-nineties. The parametrization of the spectral functions includes constraints from unitarity, perturbative QCD, and recent measurements of the neutron charge radius. We obtain a good description of most modern form factor data, with the exception of the Jefferson Lab data on G_E^p/G_M^p in the four-momentum transfer range Q²=3...6 GeV². For the magnetic radii of the proton and the neutron we find r_M^p = 0.857 fm and r_Mⁿ = 0.879 fm, which is consistent with the recent determinations using continued fraction expansions.

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