An analysis of the next-to-leading order corrections to the gT(=g1+g2) scaling function

Abstract

Abstract We present a general method for obtaining the quantum chromodynamical radiative corrections to the higher-twist (power-suppressed) contributions to inclusive deep-inelastic scattering in terms of light-cone correlation functions of the fundamental fields of quantum chromodynamics. Using this procedure, we calculate the previously unknown O (α s ) corrections to the twist-three part of the spin scaling function gT(xB,Q2)(=g1(xB,Q2)+g2(xB,Q2)) and the corresponding forward Compton amplitude ST(ν,Q2). Expanding our result about the unphysical point xB=∞, we arrive at an operator product expansion of the nonlocal product of two electromagnetic current operators involving twist-two and -three operators valid to O (α s ) for forward matrix elements. We find that the Wandzura–Wilczek relation between g1(xB,Q2) and the twist-two part of gT(xB,Q2) is respected in both the singlet and non-singlet sectors at this order, and argue its validity to all orders. The large-Nc limit does not appreciably simplify the twist-three Wilson coefficients.