CHIRAL-SYMMETRY - PION-NUCLEON INTERACTIONS IN CONSTITUENT QUARK MODELS

We study the interactions of an elementary pion with a nucleon made of constituent quarks and show that the enforcement of chiral symmetry r equires the use of a two-body operator, whose form does not depend on the choice of the pion-quark coupling. The coordinate space NN effecti ve potential in the pion exchange channel is given as a sum of terms i nvolving two gradients, which operate on both the usual Yukawa functio n and the confining potential. We also consider an application to the case of quarks bound by a harmonic potential and show that corrections due to the symmetry are important.