Evolution of the spin of the nucleon

Abstract

We compare momentum sum rules from unpolarized electroproduction and the spin sum rule for $g_1$ in polarized electroproduction, and their $Q^2$ evolution in the framework of the operator product expansion. Second order effects in ${\alpha }_s$ are included. We show that in comparing the evolution of the spin sum rule with the momentum sum rule one is not overly sensitive to using first or second order, even when going to the extreme low $Q^2$ limit in which gluons carry no momentum. Our results show that in that limit there is no need to include any contribution of strange quarks.

17 pages RevTeX, 4 uuencoded figures

References in corpus (6)

• The three-loop QCD $\beta$-function and anomalous dimensions
• The renormalization of the axial anomaly in dimensional regularization
• Measurement of the Spin-Dependent Structure Function $g_1(x)$ of the Proton
• ERRATUM TO: Power corrections $1/Q^2$ to parton sum rules for deep inelastic scattering from polarized targets
• Analysis of Data on Polarized Lepton-Nucleon Scattering
• Matrix Elements of the Singlet Axial Current in the Proton

Cited by in corpus (4)

• Next-To-Leading Order Analysis of Polarized and Unpolarized Structure Functions
• The role of orbital angular momentum in the proton spin
• Flavor structure of the unpolarized and longitudinally-polarized sea-quark distributions in the nucleon
• Evolution of Gluon Spin in the Nucleon