Quark mean field approach with alternative derivative coupling models for nuclear matter

We study nuclear matter in terms of the quark versions of the alternative derivative coupling (ZM2 and ZM3) models, in which we describe the nucleon using the constituent quark model. The couplings of the scalar and vector mesons with nucleons are made density dependent through the factor in connection with rescaling of the quark-meson Lagrangian density. The quark structure of the nucleon appears as another factor in the coupling of the scalar meson with the nucleon. The present paper provides a comparative study of our models and structureless-nucleon models.

Figure 1

Energy per nucleon $E_{\mathrm{b}}$ (MeV) of symmetric nuclear matter as a function of ${\rho }_B$ for the models. The solid curve corresponds to the q-ZM2 model. The results in the ZM2 model are plotted by dashed curve.

Figure 2

The ratio $M_{\mathrm{eff}}/M$ as a function of ${\rho }_B$ for the models. The curves are labeled as in Fig. 1.

Figure 3

The $M_{\mathrm{eff}}$ as a function of $\alpha$ at ${\rho }_0$.