Integral Relations for Twist 2 and Twist 3 Contributions to Polarized Structure Functions

We discuss the relations between the twist 2 and twist 3 contributions to polarized deep-inelastic scattering structure functions both for neutral and charged current interactions which are predicted by the operator product expansion in lowest order in QCD. INTRODUCTION In the case of polarized deep inelastic scattering the cross sections depend on (up to) three unpolarized Fi(x,Q 2)3i=1 and five polarized structure functions gj(x,Q 2)5j=1 in the limit of vanishing fermion masses. The lowest twist contributions are those of twist 2 for the structure functions Fi(x,Q ) and g1,4,5(x,Q ). The structure functions g2(x,Q ) and g3(x,Q ) contain as well twist 3 terms [1,2]. In this note we give a summary on the relations between the twist 2 and twist 3 contributions to the different structure functions in lowest order in QCD. We also comment on a sum rule which has been derived in ref. [3] recently. TWIST 2 For the twist 2 contributions to the structure functions one may seek a partonic interpretation. However, in lowest order in QCD only two generic parton combinations exist to describe the polarized structure functions : g1(x,Q ) ∝ ∆q(x,Q) + ∆q(x,Q) and g5(x,Q ) ∝ ∆q(x,Q)−∆q(x,Q). (1) 1) To appear in : Proc. of the 5th. Int. Conference on Deep Inelastic Scattering, Chicago, April, 1997 c © 1997 American Institute of Physics 1