The relativistic Dirac–Brueckner approach to asymmetric nuclear matter

Abstract

The properties of asymmetric nuclear matter have been investigated in a relativistic Dirac-Brueckner-Hartree-Fock framework using the Bonn A potential. The components of the selfenergies are extracted by projecting on Lorentz invariant amplitudes. Furthermore, the optimal representation scheme for the T matrix, the subtracted T matrix representation, is applied and the results are compared to those of other representation schemes. Of course, in the limit of symmetric nuclear matter our results agree with those found in literature. The binding energy E b fulfills the quadratic dependence on the asymmetry parameter and the symmetry energy is 34 MeV at saturation density. Furthermore, a neutron-proton effective mass splitting of m * n < m * p is found.In addition, results are given for the mean-field effective coupling constants.

Fast nucleon emission as a probe of the momentum dependence of the symmetry potential

“…We note that the same is predicted from microscopic relativistic Dirac-Brueckner-Hartree-Fock (DBHF ) calculations [10,11,12] and in general from the introduction of scalar isovector virtual mesons in Relativistic Mean Field (RM F ) approaches [13,14]. At variance, non-relativistic Brueckner-Hartree-Fock (BHF ) calculations are leading to opposite conclusions [15,16,17].…”

Probing the density dependence of the symmetry potential in intermediate-energy heavy ion collisions

“…More recently, a new value of S 0 ≃ 31 MeV was obtained, based on the consistent folding analysis of the p( 6 He, 6 He)p elastic scattering and p( 6 He, 6 Li * )n charge exchange reaction data measured at E Lab = 41.6 MeV [26], while S 0 = 34 MeV was obtained in a calculation made within the relativistic Brueckner framework, using the Bonn A potential [27]. Thus, it is necessary to further investigate the uncertainty of the S 0 value [28].…”

Off-shell behavior of nucleon self-energy in asymmetric nuclear matter

“…The approach is roughly based on the ones in Ref. [16,17], with the exception of some modifications to separate the momentum and energy dependence. First a general overview is given, followed by a discussion of the modifications.…”

“…To achieve this reduction to the one-dimensional integral equations the Pauli operator Q is replaced by an angle-averaged Pauli operator Q [8]. For more details we refer to [16,17].…”

“…However, relativistic microscopic DBHF investigations of isospin asymmetric nuclear matter are rather rare [13][14][15][16][17]. Furthermore, all these studies are restricted to the on-shell behavior of nucleon properties in contrast to some microscopic non-relativistic investigations, which do include the study of off-shell behavior of these properties in isospin asymmetric nuclear matter [18,19].…”