NUCLEAR-MATTER PROPERTIES FOR MODIFIED ZIMANYI-MOSZKOWSKI MODELS

Effective Lagrangians involving nucleons coupled to scalar and vector fields are investigated within the framework of relativistic mean-fiel d theory. The study presents the traditional Walecka model acid differ ent kinds of scalar derivative coupling suggested by Zimanyi and Moszk owski (ZM). it is shown that the equations of state for all these modi fied ZM models are soft. The real part of the optical potential for th ese models is obtained. When compared with the usual ZM model, the mod ified models present the peculiarity of giving simultaneously a smalle r nucleon effective mass and a smaller incompressibility. This can be explained through the mesonic nonlinear sealar-vector coupling contain ed in these modified models.