Spin symmetry in Dirac negative energy spectrum in density-dependent relativistic Hartree-Fock theory

摘要

The spin symmetry in the Dirac negative energy spectrum and its origin areinvestigated for the first time within the density-dependent relativisticHartree-Fock (DDRHF) theory. Taking the nucleus $^{16}$O as an example, thespin symmetry in the negative energy spectrum is found to be a goodapproximation and the dominant components of the Dirac wave functions for thespin doublets are nearly identical. In comparison with the relativistic Hartreeapproximation where the origin of spin symmetry lies in the equality of thescalar and vector potentials, in DDRHF the cancellation between the Hartree andFock terms is responsible for the better spin symmetry properties anddetermines the subtle spin-orbit splitting. These conclusions hold even in thecase when significant deviations from the G-parity values of themeson-antinucleon couplings occur.