On the transformation between current and constituent quarks and consequences for polarised electroproduction structure functions

The transformation of Buccella et al. (1970) and of Melosh (1973) is a rotation in spin space, so spin-dependent matrix elements are sensitive to this transformation, while spin-averaged quantities are not. This is shown by applying this transformation to the nucleon constituent space SU(6) wave function. Matrix elements of current operators are calculated with special emphasis on polarised electroproduction. It is shown that the current quarks generated by this transformation cannot be identified with quark partons and the properties of a more general operator for such a transformation are discussed. The nucleon octet states are decomposed into SU(6) parton configurations and elastic and inelastic matrix elements within the octet are computed. A sum rule is derived for the asymmetry in polarised electroproduction on polarised protons. (45 refs).