On Electroweak Moments of Baryons and Spin-Flavour Structure of the Nucleon
Abstract
Description
The phenomenological sum-rule-based approach is used to discuss the quark composition dependence of some static and quasi-static electroweak characteristics of nucleons.The role of nonvalence degrees of freedom, the nucleon sea partons and/or peripheral meson currents, is shown to be important to select and make use of the relevant symmetry parametrization of hadron observables. With our preferable universal value of the SU(3)-symmetry parameter $α_{D}=D/F+D=.58$, taken for both magnetic moments and axial-vector constants entering into the semi-leptonic baryon decays, we obtain the following values for moments $Δq$ of the spin-dependent structure function of the proton: $Δu \simeq .84(.82), Δd \simeq -.42(-.44), Δs=-.22 \pm .05 (-.10 \pm .03)$, where the values in parentheses correspond to the widely used "standard" value of $α^{axial}_{D}=.63$. The estimations of the strange sea contributions to the nucleon magnetic moments and rms are also presented.
8 pages, Latex, no figures, Talk given at the VII-th International Workshop on High Energy Spin Physics, Dubna, 7-12 July 1997, to be published in Proceedings
8 pages, Latex, no figures, Talk given at the VII-th International Workshop on High Energy Spin Physics, Dubna, 7-12 July 1997, to be published in Proceedings