Year: 2000
Type: article
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 $\ensuremath{\sigma}$ term and on-shell $\ensuremath{\sigma}$-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 $\ensuremath{\sim}20%$ to the magnitude of ${g}_{A}.$ The calculation of the nucleon $\ensuremath{\sigma}$ term elucidates the only unambiguous means of extrapolating meson-nucleon couplings off the meson mass shell.
Source: Physical Review C
Authors: J. C. R. Bloch, C. D. Roberts, S. M. Schmidt
Institution: Argonne National Laboratory
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2027756199