Selected nucleon form factors and a composite scalar diquark
Nuclear Theory
2009-01-14 v1 High Energy Physics - Lattice
High Energy Physics - Phenomenology
Nuclear Experiment
Abstract
A covariant, composite scalar diquark, Fadde'ev amplitude model for the nucleon is used to calculate pseudoscalar, isoscalar- and isovector-vector, axial-vector and scalar nucleon form factors. The last yields the nucleon sigma-term and on-shell sigma-nucleon coupling. The calculated form factors are soft, and the couplings are generally in good agreement with experiment and other determinations. Elements in the dressed-quark-axial-vector vertex that are not constrained by the Ward-Takahashi identity contribute ~20% to the magnitude of g_A. The calculation of the nucleon sigma-term elucidates the only unambiguous means of extrapolating meson-nucleon couplings off the meson mass-shell.
Keywords
Cite
@article{arxiv.nucl-th/9911068,
title = {Selected nucleon form factors and a composite scalar diquark},
author = {J. C. R. Bloch and C. D. Roberts and S. M. Schmidt},
journal= {arXiv preprint arXiv:nucl-th/9911068},
year = {2009}
}
Comments
12 pages, REVTEX, 5 figures, epsfig