Infrared renormalons and power corrections in deep inelastic sum rules

Abstract Infrared renormalons and 1/ Q 2 power corrections in deep-inelastic sum rules are studied. The renormalization of composite operators with power divergence is discussed. The higher-twist terms in the operator product expansion are shown to account for the residual soft contributions survived from the Kinoshita-Lee-Nauenberg type of cancellations in Feynman diagrams. The discussion is focused on the Bjorken sum rule, for which the 1/ Q 2 correction is taken into account through a twist-four operator defined with the “minimal subtraction” of quadratic divergence.