{
  "id": "1602.08106",
  "version": "v1",
  "published": "2016-02-25T21:01:01.000Z",
  "updated": "2016-02-25T21:01:01.000Z",
  "title": "Equation of state for neutron stars with hyperons by the variational method",
  "authors": [
    "H. Togashi",
    "E. Hiyama",
    "Y. Yamamoto",
    "M. Takano"
  ],
  "comment": "12 pages, 6 figures, accepted for publication in Phys. Rev. C",
  "categories": [
    "nucl-th",
    "astro-ph.HE"
  ],
  "abstract": "We investigate the effects of the odd-state part of bare $\\Lambda \\Lambda$ interactions on the structure of neutron stars (NSs) by constructing equations of state (EOSs) for uniform nuclear matter containing $\\Lambda$ and $\\Sigma^-$ hyperons with use of the cluster variational method. The isoscalar part of the Argonne v18 two-nucleon potential and the Urbana IX three-nucleon potential are employed as the interactions between nucleons, whereas, as the bare $\\Lambda N$ and even-state $\\Lambda \\Lambda$ interactions, two-body central potentials that are determined so as to reproduce the experimental data on single- and double-$\\Lambda$ hypernuclei are adopted. In addition, the $\\Sigma^- N$ interaction is constructed so as to reproduce the empirical single-particle potential of $\\Sigma^-$ in symmetric nuclear matter. Since the odd-state part of the $\\Lambda \\Lambda$ interaction is not known owing to lack of experimental data, we construct four EOSs of hyperonic nuclear matter, each with a different odd-state part of the $\\Lambda \\Lambda$ interaction. The EOS obtained for NS matter becomes stiffer as the odd-state $\\Lambda \\Lambda$ interaction becomes more repulsive, and correspondingly the maximum mass of NSs increases. It is interesting that the onset density of $\\Sigma^-$ depends strongly on the repulsion of the odd-state $\\Lambda \\Lambda$ interaction. Furthermore, we take into account the three-baryon repulsive force to obtain results that are consistent with observational data on heavy NSs.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-02-25T21:01:01.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "variational method",
      "neutron stars",
      "interaction",
      "odd-state part",
      "experimental data"
    ],
    "publication": {
      "doi": "10.1103/PhysRevC.93.035808"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 12,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1424500
    }
  }
}