Spin-asymmetry energy of nuclear matter

Abstract

We calculate the density-dependent spin-asymmetry energy $S(k_f)$ of isospin-symmetric nuclear matter in the three-loop approximation of chiral perturbation theory. The interaction contributions to $S(k_f)$ originate from one-pion exchange, iterated one-pion exchange, and (irreducible) two-pion exchange with no, single, and double virtual $\Delta$-isobar excitation. We find that the truncation to $1\pi$-exchange and iterated $1\pi$-exchange terms (which leads already to a good nuclear matter equation of state) is spin-unstable, since $S(k_{f0})<0$. The inclusion of the chiral $\pi N\Delta$-dynamics guarantees the spin-stability of nuclear matter. The corresponding spin-asymmetry energy $S(k_f)$ stays positive within a wide range of an undetermined short-range parameter $S_5$ (which we also estimate from realistic NN-potentials). Our results reemphasize the important role played by two-pion exchange with virtual $\Delta$-isobar excitation for the nuclear matter many-body problem. Its explicit inclusion is essential in order to obtain good bulk and single-particle properties.

11 pages, 6 figuers, accepted for publication in Physical Review C

References in corpus (3)

• A microscopic estimate of the nuclear matter compressibility and symmetry energy in relativistic mean-field models
• Chiral approach to nuclear matter: Role of two-pion exchange with virtual delta-isobar excitation
• Single-particle potential in a chiral approach to nuclear matter including short range NN-terms

Cited by in corpus (10)

• Chiral approach to nuclear matter: Role of two-pion exchange with virtual delta-isobar excitation
• In-medium chiral condensate beyond linear density approximation
• Spin polarized neutron matter within the Dirac-Brueckner-Hartree-Fock approach
• Spin- and isospin-polarized states of nuclear matter in the Dirac-Brueckner-Hartree-Fock model
• Spin-polarized neutron matter at different orders of chiral effective field theory
• Quasi-particle interaction in nuclear matter from chiral pion-nucleon dynamics
• Nuclear matter symmetry energy from generalized polarizabilities: dependences on momentum, isospin, density and temperature
• The splitting of the one-body potential in spin-polarized isospin-symmetric nuclear matter
• Isospin-Asymmetry Dependence of the Thermodynamic Nuclear Equation of State in Many-Body Perturbation Theory
• Spin-isospin stability of nuclear matter