Scalar and vector decomposition of the nucleon self-energy in the relativistic Brueckner approach

Fuchs, C.;Waindzoch, T.;Faessler, Amand;Kosov, D.S.

Abstract

We investigate the momentum dependence of the nucleon self-energy in nuclear matter. We apply the relativistic Brueckner-Hartree-Fock approach and adopt the Bonn A potential. A strong momentum dependence of the scalar and vector self-energy components can be observed when a commonly used pseudovector choice for the covariant representation of the T matrix is applied. This momentum dependence is dominated by the pion exchange. We discuss the problems of this choice and its relations to on-shell ambiguities of the T matrix representation. Starting from a complete pseudovector representation of the T matrix, which reproduces correctly the pseudovector pion-exchange contributions at the Hartree-Fock level, we observe a much weaker momentum dependence of the self-energy. This fixes the range of the inherent uncertainty in the determination of the scalar and vector self-energy components. Comparing to other work, we find that extracting the self-energy components by a fit to the single particle potential leads to even more ambiguous results.

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1089-490X

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American Physical Society

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DOI

10.1103/PhysRevC.58.2022