Effective masses of pentaquark ⊖+ in nuclear matter

The properties of baryons in nuclear matter are analysed in the relativistic mean-field theory(RMF). It is found that the scalar field σ meson affects the properties of baryon at high density. A density dependent scalar coupling gσ N is determined according to the idea of quark-meson coupling model and extended to RMF. It is shown that g σ N affects the property of nuclear matter weakly at low density, but strongly at high density. The relation between the scalar density ps and the nuclear density p and the effective mass of the pentaquark ⊖+ are studied with the density dependent coupling constant. The density dependent scalar coupling obviously affects the effective masses of baryons in nuclear matter, especially at high density.