Interactions of η-meson in asymmetric nuclear matter

Abstract

Abstract The interactions between η-meson and nucleons are studied by the unification of the chiral SU(3) model and chiral perturbation theory. The η meson-nucleon interactions for the next-to-leading order terms are derived by expanding the ηN interaction Lagrangian within the chiral perturbation theory. Using the chiral SU(3) model, we calculate the in-medium scalar density of protons ρ s p and neutrons ρ s n for different values of temperature T, isospin asymmetry I and nucleonic density ρN. Within the chiral SU(3) model the in-medium properties of nucleons are evaluated in terms of scalar-isoscalar fields σ, and ζ and the scalar-isovector field δ. The scalar densities of nucleons calculated using chiral SU(3) model are used as input in the equation of motion of η mesons obtained from chiral perturbation theory. We solve the equation of motion for sigma term Σ η N = 280 ± 130 MeV and scattering length aηN = 1.025 fm for different values of asymmetry of the medium. We find an attractive mass-shift of the η meson in nuclear medium and the magnitude of this shift increases with increasing density. Finite isospin asymmetry of the medium causes less drop in the in-medium mass of η mesons. The negative mass-shift indicates the possibility of the formation of η-mesic nuclei.