Dispersion Analysis of the Strange Vector Form Factors of the Nucleon

Abstract

We analyze the nucleon matrix element of the strange quark vector current in a nucleon--model independent dispersive approach with input from the current world data set for the isoscalar electromagnetic form factors. The update of Jaffe's minimal 3-pole ansatz for the spectral functions yields a 40% larger (Sachs) strangeness radius, $(r_s^2{)}_{Sachs}=0.20{\mathrm{fm}}^2$, and a by 20% reduced magnitude of the strangeness magnetic moment, ${\mu }_s=-0.26$. In the pole approximation these values are shown to be upper bounds. After extending the ansatz in order to implement the asymptotic QCD momentum dependence (which the 3-pole form factors cannot reproduce), we find the magnitude of the 3-pole results reduced by up to a factor of 2.5. The signs of the leading moments originate primarily from the large $\varphi$-meson couplings and are generic in the pole approximation.

41 pages, RevTeX file and 4 postscript figures

References in corpus (3)

• The Strangeness Radius and Magnetic Moment of the Nucleon Revisited
• QCD Equalities for Baryon Current Matrix Elements
• Strangeness in the Nucleon: The Strange Vector Form Factors

Cited by in corpus (17)

• Nucleon electromagnetic form factors
• The Strange Quark Contribution to the Proton's Magnetic Moment
• Parity-violating electroweak asymmetry in $\vec{e}p$ scattering
• The SAMPLE Experiment and Weak Nucleon Structure
• Strange nucleon form factors in the perturbative chiral quark model
• Strange magnetic form factor of the proton at $Q^2=0.23$ GeV${}^2$
• Dispersion-theoretical analysis of the electromagnetic form factors of the nucleon: Past, present and future
• Strange form factors in the context of SAMPLE, HAPPEX, and A4 experiments
• K\bar{K}-Continuum and Isoscalar Nucleon Form Factors
• Spectral Content of Isoscalar Nucleon Form Factors
• K^* Mesons and Nucleon Strangeness
• Strangeness content of the nucleon in quasielastic neutrino-nucleus reactions
• K* nucleon hyperon form factors and nucleon strangeness
• Helicity asymmetries in neutrino-nucleus interactions
• Strange magnetic moment of the nucleon and SU(3) breaking: group theoretical approach
• Study of a WIMP dark matter model with the updated results of CDMS II
• Strange Vector Form Factor of Kaons