Properties of N* (1535) at finite density in the extended parity-doublet models

We improve so-called ''naive'' and ''mirror'' models for the positive and negative parity nucleons, N and N*, by introducing non-linear terms allowed by chiral symmetry. Both models in this improvement reproduce the observed nucleon axial charge in free space and reveal interesting density dependence of the axial charges for N and N*, and the doublet masses. A remarkable difference between the two models is found in the off-diagonal axial charge, gANN*, which could appear either as suppression or as enhancement of N* → πN decay in the medium. (orig.)