Off-shell pairing correlations from meson-exchange theory of nuclear forces

Abstract

We develop a model of off-mass-shell pairing correlations in nuclear systems, which is based on the meson-exchange picture of nuclear interactions. The temporal retardations in the model are generated by the Fock-exchange diagrams. The kernel of the complex gap equation for baryons is related to the in-medium spectral function of mesons, which is evaluated nonperturbatively in the random phase approximation. The model is applied to the low-density neutron matter in neutron star crusts by separating the interaction into a long-range one-pion-exchange component and a short-range component parametrized in terms of Landau Fermi liquid parameters. The resulting Eliashberg-type coupled nonlinear integral equations are solved by an iterative procedure.We find that the self-energies extend to off-shell energies of the order of several tens of MeV. At low energies the damping of the neutron pair correlations due to the coupling to the pionic modes is small, but becomes increasingly important as the energy is increased. We discuss an improved quasiclassical approximation under which the numerical solutions are obtained.

15 pages, 7 figures, uses RevTeX 4; v2: substantially expanded version to appear in PRC

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Cited by in corpus (9)

• Superfluidity in nuclear systems and neutron stars
• Pairing in high-density neutron matter including short- and long-range correlations
• Pairing in high-density neutron matter including short- and long-range correlations
• Pairing properties of nucleonic matter employing dressed nucleons
• Vertex renormalization in weak decays of Cooper pairs and cooling compact stars
• Superfluid nucleon matter in and out of equilibrium and weak interactions
• Color superconductivity from the chiral quark-meson model
• ${}^1{S}_0$ pairing for neutrons in dense neutron matter induced by a soft pion
• Pion-mediated Cooper pairing of neutrons: beyond the bare vertex approximation