Strange form factors, the σ-term and strange quark distributions in the Gross-Neveu model

Abstract

For N c→∞ the structure function of physical fermions in the Gross-Neveu model is of pure valence type. Nevertheless several strange form factors of u-quarks, including the induced magnetic moment and the σ-term acquire substantial O(N 0 c ) contributions from virtual ss pairs. Those arise from matrix elements which are off-diagonal in Fock space, i.e., they do not have a simple interpretation in terms of the quark distributions. It is shown that, under certain circumstances, a similar behavior in QCD 3+1 is conceivable.