Nucleon electromagnetic and axial-vector form factors in the context of bag models.

Abstract

We investigate the procedure which one uses to calculate the nucleon form factors, for both the electromagnetic and axial-vector currents, from bag models. We first point out that these form factors, as functions of ${q}^{2}$ alone, can in general be expressed in terms of several matrix elements, all of which are defined in the Breit frame. We then evaluate these Breit-frame matrix elements by assuming both (1) that the current operators can be approximated by the one-body quark contribution, and (2) that the nucleon wave functions at rest can be approximated by those given in the MIT bag model. Typical numerical results, as augmented by pionic corrections, provide a reasonable description of the experimental data.