Three-body force effect on the neutron and proton spectral functions in asymmetric nuclear matter

Abstract

We investigate the effect of microscopic three-body forces (TBFs) on the off-shell behavior of the neutron and proton mass operators ${M}^{\ensuremath{\tau}}(k,\ensuremath{\omega})={V}^{\ensuremath{\tau}}(k,\ensuremath{\omega})+i{W}^{\ensuremath{\tau}}(k,\ensuremath{\omega})$ in asymmetric nuclear matter within the framework of the extended Brueckner-Hartree-Fock approach. We adopt the Argonne ${V}_{18}$ two-body potential supplemented with a microscopic TBF as the realistic nucleon-nucleon interaction. At high densities well above the normal nuclear matter density, the TBF turns out to affect significantly the off-shell behavior of both the proton and neutron mass operators. The neutron and proton spectral functions in asymmetric nuclear matter are calculated and discussed. At low densities around and below the normal density, the TBF effect on the spectral functions turns out to be negligibly weak. At high densities well above the saturation density, the TBF is shown to affect noticeably the neutron and proton spectral functions.