Eur. Phys. J. A (2010) 44: 119-124
https://doi.org/10.1140/epja/i2010-10938-6

Regular Article - Theoretical Physics

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

¹ State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, 100871, Beijing, China
² Institut de Physique Nucléaire, IN2P3-CNRS and Université Paris-Sud, F-91406, Orsay Cedex, France
³ Physik-Department der Technischen Universität München, D-85748, Garching, Germany
⁴ School of Physics and Nuclear Energy, Beihang University, 100191, Beijing, China
⁵ Department of Physics, University of Stellenbosch, Stellenbosch, South Africa

^* e-mail: mengj@pku.edu.cn

Received: 9 October 2009
Revised: 27 December 2009
Accepted: 15 February 2010
Published online: 11 March 2010

Abstract

The spin symmetry in the Dirac negative-energy spectrum and its origin are investigated for the first time within the density-dependent relativistic Hartree-Fock (DDRHF) theory. Taking the nucleus ¹⁶O as an example, the spin symmetry in the negative-energy spectrum is found to be a good approximation and the dominant components of the Dirac wave functions for the spin doublets are nearly identical. In comparison with the relativistic Hartree approximation where the origin of spin symmetry lies in the equality of the scalar and vector potentials, in DDRHF the cancellation between the Hartree and Fock terms is responsible for the better spin symmetry properties and determines the subtle spin-orbit splitting. These conclusions hold even in the case when significant deviations from the G -parity values of the meson-antinucleon couplings occur.