CHIRAL-SYMMETRY AND THE NUCLEON STRUCTURE FUNCTIONS

The flavor asymmetry of the sea quark distribution as well as the unex pectedly small quark spin fraction of the nucleon are two outstanding discoveries recently made in the physics of deep-inelastic structure f unctions. We evaluate here the corresponding quark distribution functi ons within the framework of the chiral quark soliton model, which is a n effective quark model of baryons maximally incorporating the most im portant feature of low-energy QCD, i.e., chiral symmetry and its spont aneous breakdown. It is shown that the model can explain qualitative f eatures of the above mentioned nucleon structure functions within a si ngle framework, thereby disclosing the importance of chiral symmetry i n the physics of high-energy deep-inelastic scattering.