The Angular Momentum and g_1^p Sum Rules for the Proton

Abstract

The gauge invariant operator formulation of the angular momentum sum rule $\frac{1}{2}=J_q+J_g$ for the proton is presented and contrasted with the sum rule for the first moment of the polarised structure function $g_1^p$. The decoupling of the axial charge $a^0$ from the angular momentum sum rule is highlighted and the possible QCD field-theoretic basis for an angular momentum sum rule of the form $\frac{1}{2}=\frac{1}{2}\text{D}q+\text{D}g+L_q+L_g$ is critically discussed.

Comments: 5 pages, LaTeX, uses espcrc2.sty; invited talk at QCD00, Montpellier, July 2000