Hadron structure functions in a chiral quark model: regularization, scaling and sum rules

We provide a consistent regularization procedure for calculating hadron str ucture functions in a chiral quark model, The structure functions are extra cted from the absorptive part of the forward Compton amplitude in the Bjork en limit. Since this amplitude is obtained as a time-ordered correlation fu nction its regularization is consistently determined from the regularizatio n of the bosunized action. We find that the Pauli-Villars regularization sc heme is most suitable because it preserves both the anomaly structure of QC D and the leading scaling behavior of hadron structure functions in the Bjo rken limit, We show that this procedure yields the correct pion structure f unction. In order to render the sum rules of the regularized polarized nucl eon structure functions consistent with their corresponding axial charges w e find it mandatory to further specify the regularization procedure. This s pecification goes beyond the double subtraction scheme commonly employed wh en studying static hadron properties in this model. In particular the prese nt approach serves to determine the regularization prescription for structu re functions whose leading moments are not given by matrix elements of loca l operators. In this regard we conclude somewhat surprisingly that in this model the Gottfried sum rule does not undergo regularization. (C) 1999 Else vier Science B,V. All rights reserved.