Quark-parton model for the structure functionW2of the proton and neutron in their rest systems

Abstract

The deep-inelastic structure function $W_2$ is calculated using the impulse approximation for mass-shell partons in the target-nucleon rest system. Bjorken scaling and the approach to scaling are shown to follow from parton kinematics in the rest system. The partons are identified as quarks and a simple harmonicoscillator quark model is used to fit the proton and neutron structure functions down to $x\sim 0.1$. The neutron structure function requires an inherently non-SU(6) quark model based on relative coordinates that we argue should replace shell-model SU(6) quark models that have been used extensively.