Tsuneo UEMATSU | Searcharxiv

arXiv1995

Target Mass Corrections to QCD Bjorken Sum Rule for Nucleon Spin Structure Functions

We discuss the possible target mass corrections in the QCD analysis of nucleon's spin-dependent structure functions measured in the polarized deep-inelastic leptoproduction. The target mass correction for the QCD Bjorken sum rule is obtained from the Nachtmann moment and its magnitude is estimated employing positivity bound as well as the experimental data for the asymmetry parameters. We also study the uncertainty due to target mass effects in determining the QCD effective coupling constant $α_s(Q^2)$ from the Bjorken sum rule. The target mass effect for the Ellis-Jaffe sum rule is also briefly discussed.

hep-ph↗

arXiv1994

Spin Structure Function $g_2$ and Twist-3 Operators in QCD

We investigate the spin structure function $g_2 (x, Q^2 )$ in the framework of the operator product expansion and the renormalization group. The twist-3 operators appearing in QCD are examined and their relations are studied. It is noted that operators proportional to equation of motion appear in the operator mixing through renormalization, which can be studied from the relevant Green's functions. We also note that the coefficient functions can be properly fixed after the choice of independent operators.

hep-ph↗