Chiral symmetry and the nucleon structure functions

Abstract
The flavor asymmetry of the sea quark distribution as well as the unexpectedly small quark spin fraction of the nucleon are two outstanding discoveries recently made in the physics of deep-inelastic structure functions. We evaluate here the corresponding quark distribution functions within the framework of the chiral quark soliton model, which is an effective quark model of baryons maximally incorporating the most important feature of low-energy QCD, i.e., chiral symmetry and its spontaneous breakdown. It is shown that the model can explain qualitative features of the abovementioned nucleon structure functions within a single framework, thereby disclosing the importance of chiral symmetry in the physics of high-energy deep-inelastic scattering.