Spectra of anti-nucleons in the vacuum of finite nuclei
The quantum vacuum in a many-body system of finite nuclei has been investigated within the relativistic Hartree approach which describes the bound states of nucleons and anti-nucleons consistently. The contributions of the Dirac sea to the source terms of the meson-field equations are taken into account up to the one-nucleon loop and one-meson loop. The tensor couplings for the omega- and rho-meson are included in the model. After adjusting the parameters of the model to the properties of spherical nuclei, a large effective nucleon mass m(*)/M-N approximate to 0.78 is obtained. The overall nucleon spectra of shell-model states are in agreement with the data. The computed anti-nucleon spectra in the vacuum differ about 20-30MeV with and without the tensor-coupling effects.