{
  "annotation_id": "219f91f6-d0ba-4e71-ae7b-3f928d212169",
  "date_created": "2026-03-02T18:00:01.126000Z",
  "date_modified": "2026-03-02T18:00:01.126000Z",
  "file_hash": "792e507bf058ac14cfa7f07e68c8702ce365e871d59ddf46596165a3f3d0c404",
  "private": false,
  "record": {
    "abstract": "We extend a recent three-loop calculation of nuclear matter in chiral\nperturbation theory by including the effects from two-pion exchange with single\nand double virtual $\\Delta(1232)$-isobar excitation. Regularization dependent\nshort-range contributions from pion-loops are encoded in a few NN-contact\ncoupling constants. The empirical saturation point of isospin-symmetric nuclear\nmatter, $\\bar E_0 = -16 $MeV, $\\rho_0 = 0.16 $fm$^{-3}$, can be well reproduced\nby adjusting the strength of a two-body term linear in density (and weakening\nan emerging three-body term quadratic in density). The nuclear matter\ncompressibility comes out as $K = 304 $MeV. The real single-particle potential\n$U(p,k_{f0})$ is substantially improved by the inclusion of the chiral $\\pi\nN\\Delta$-dynamics: it grows now monotonically with the nucleon momentum $p$.\nThe effective nucleon mass at the Fermi surface takes on a realistic value of\n$M^*(k_{f0})=0.88M$. As a consequence of these features, the critical\ntemperature of the liquid-gas phase transition gets lowered to the value $T_c\n\\simeq 15 $MeV. In this work we continue the complex-valued single-particle\npotential $U(p,k_f)+i W(p,k_f)$ into the region above the Fermi surface\n$p\u003ek_f$. The effects of $2\\pi$-exchange with virtual $\\Delta$-excitation on the\nnuclear energy density functional are also investigated. The effective nucleon\nmass associated with the kinetic energy density is $\\widetilde M^*(\\rho_0)=\n0.64M$. Furthermore, we find that the isospin properties of nuclear matter get\nsignificantly improved by including the chiral $\\pi N\\Delta$-dynamics.",
    "arxiv_id": "nucl-th/0406038",
    "authors": [
      "S. Fritsch",
      "N. Kaiser",
      "W. Weise"
    ],
    "categories": [
      "nucl-th"
    ],
    "doi": "10.1016/j.nuclphysa.2004.12.042",
    "journal_ref": "Nucl.Phys. A750 (2005) 259-293",
    "title": "Chiral approach to nuclear matter: Role of two-pion exchange with   virtual delta-isobar excitation",
    "url": "https://arxiv.org/abs/nucl-th/0406038"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "542361a5-c4a4-4b13-8089-869fcbecefd4",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}