Göttingen 1997 – wissenschaftliches Programm

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HK: Hadronen und Kerne

HK 5: Kernspektroskopie, schwere Kerne I

HK 5.7: Vortrag

Montag, 24. März 1997, 15:45–16:00, HS F

A Relativistic Brueckner Approach For Nuclear Matter — • L.Sehn, C.Fuchs, and A.Faessler — Institut f"ur Theoretische Physik, Universit"at T"ubingen, Auf der Morgenstelle 14, D-72076 T"ubingen

The relativistic two-nucleon correlation in infinite nuclear matter is studied in the framework of the relativistic (or Dirac-) Brueckner approach. The formalism is based on an effective quantum field theory for mesons and nucleons. The two-nucleon correlation, given by the T-matrix, is determined by a self-consistent summation of the ladder diagrams in a quasipotential approximation (Thompson equation) of the Bethe-Salpeter equation. As nucleon-nucleon (ladder) interaction, described by one-boson exchange potentials, the Bonn potentials A,B,C and for comparison the Walecka model are used. Self-consistency modifies the single-particle spectrum and introduces a density dependence in the self-consistent spinor-basis and so in the matrix elements. The nucleon inside the nuclear medium is a dressed Dirac particle, where the influence of the coupling to the surrounding nucleons is expressed by a self-energy, which has a Lorentz structure with large scalar and vector components. These fields are density dependent and the influence of the pseudovector and the pseudoscalar projection of the T-matrix is discussed. The relativistic Brueckner approach treats (in first order) also the momentum dependence of the fields, which is found to be rather strong inside the Fermi sea. The binding energy (e.o.s) and the Schroedinger equivalent optical potential are shown.