QCD Sum Rule Calculation of Twist-4 Corrections to Bjorken and Ellis-Jaffe Sum Rules

E. Stein; P. Gornicki; L. Mankiewicz; A. Schaefer

doi:10.1016/0370-2693(95)00544-U

paper

QCD Sum Rule Calculation of Twist-4 Corrections to Bjorken and Ellis-Jaffe Sum Rules

arXiv:hep-ph/9502323 · doi:10.1016/0370-2693(95)00544-U

Abstract

We calculate the twist-4 corrections to the integral of $g_{1} (x, Q^{2})$ in the framework of QCD sum rules using an interpolating nucleon field which contains explicitly a gluonic degree of freedom. This information can be used together with previous calculations of the twist-3 contribution to the second moment of $g_{2} (x)$ to estimate the higher-twist corrections to the Ellis-Jaffe and Bjorken sum rules. We get $f^{(2)} (p r o t o n) = - 0.037 \pm 0.006$ and $f^{(2)} (n e u t r o n) = - 0.013 \pm 0.006$ . Numerically our results roughly agree with those obtained by Balitsky, Braun and Kolesnichenko based on a sum rule for a simpler current. Our calculations are far more stable as tested within the sum rule approach but are more sensitive to less well known condensates.

18pp., 1 figure (uuencoded eps-file), LateX