DOES THE NUCLEAR MEDIUM REACT AGAINST CHIRAL-SYMMETRY RESTORATION

It has recently been suggested that distortion effects due to rescatte ring of soft pions tend to reduce the sigma commutator per nucleon in heavy nuclei. We point out that the sigma commutator can always be cal culated directly as a symmetry-breaking matrix element. The rescatteri ng term should not be treated separately from other terms of similar m agnitude. We illustrate this is in the linear sigma model where the fu ll amplitude for soft-pion scattering from two nucleons is equivalent to the contribution to the commutator from sigma exchange between the nucleons. This leads instead to an enhancement of chiral symmetry rest oration, although we expect it to be partly cancelled by omega exchang e and the effects of correlations.