Chiral dynamics and nuclear matter

N. Kaiser, S. Fritsch, W. Weise

Research output: Contribution to journalArticlepeer-review

182 Scopus citations

Abstract

We calculate the equation of state of isospin-symmetric nuclear matter in the three-loop approximation of chiral perturbation theory. The contributions to the energy per particle Ē(kf)from one- and two-pion exchange diagrams are ordered in powers of the Fermi momentum kf (modulo functions of kf/mπ). It is demonstrated that, already at order script O sign(kf4), two-pion exchange produces realistic nuclear binding. The underlying saturation mechanism is surprisingly simple (in the chiral limit), namely the combination of an attractive kf 3-term and a repulsive kf4-term. The empirical saturation point and the nuclear compressibility K ≃ 250 MeV are well reproduced at order script O sign(kf5) with a momentum cut-off of Λ ≃ 0.65 GeV which parameterizes short-range dynamics. No further short-distance terms are required in our calculation of nuclear matter. In the same framework we calculate the density-dependent asymmetry energy and find A0 ≃ 34 MeV at the saturation point, in good agreement with the empirical value. The pure neutron matter equation of state is also in fair qualitative agreement with sophisticated many-body calculations and a resummation result of effective field theory, but only for low neutron densities ρn < 0.25 fm-3.

Original languageEnglish
Pages (from-to)255-276
Number of pages22
JournalNuclear Physics, Section A
Volume697
Issue number1-2
DOIs
StatePublished - 14 Jan 2002

Keywords

  • Asymmetry energy
  • Effective field theory at finite density
  • Neutron matter
  • Nuclear matter equation of state

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