{
  "id": "1007.4125",
  "version": "v1",
  "published": "2010-07-23T13:27:57.000Z",
  "updated": "2010-07-23T13:27:57.000Z",
  "title": "$α+α+t$ cluster structures and Hoyle-analogue states in $^{11}$B",
  "authors": [
    "Taiichi Yamada",
    "Yasuro Funaki"
  ],
  "comment": "22 pages, 9 figures",
  "journal": "Phys.Rev.C82:064315,2010",
  "doi": "10.1103/PhysRevC.82.064315",
  "categories": [
    "nucl-th"
  ],
  "abstract": "The structure of $3/2^{-}$ and $1/2^{+}$ states in $^{11}$B is investigated with an $\\alpha+\\alpha+t$ orthogonality condition model (OCM) based on the Gaussian expansion method. Full levels up to the $3/2^{-}_{3}$ and $1/2^{+}_2$ states around the $\\alpha+\\alpha+t$ threshold ($E_x$=11.1 MeV) are reproduced consistently with the experimental energy levels. It is shown that the $3/2_{3}^{-}$ state located around the $^{7}$Li+$\\alpha$ threshold has an $\\alpha+\\alpha+t$ cluster structure, whereas the $3/2_{1}^{-}$ and $3/2_{2}^{-}$ states have a shell-model-like compact structure. We found that the $3/2_{3}^{-}$ state does not possess an $\\alpha$-condensate-like nature similar to the $0^{+}_{2}$ state of $^{12}$C (Hoyle state) which has a dilute $3\\alpha$-condensate structure described by a $(0S_{\\alpha})^3$ configuration with about $70$\\% probability, although the monopole transition strength of the former is as large as that of the latter. We discuss the reasons why the $3/2_{3}^{-}$ state does not have the condensate character. On the other hand, the $1/2^{+}_{1}$ state just below the $^{7}$Li+$\\alpha$ threshold has a cluster structure which can be interpreted as a parity-doublet partner of the $3/2^{-}_3$ state. We indicate that the $12.56$-MeV state ($J^{\\pi}=1/2^{+}_{2}$) just above the $\\alpha+\\alpha+t$ threshold observed in the $^7$Li($^{7}$Li,$^{11}$B$^*$)$t$ reaction etc. is of the dilute-cluster-gas-like, and is a strong candidate for the Hoyle-analogue state which has a configuration of $(0S_{\\alpha})^{2}(0S_{t})$ with about $65$\\% probability from the analyses of the single-cluster motions in $^{11}$B. The structure property of the $1/2^{+}$ resonant state is analyzed with the complex scaling method.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2010-07-23T13:27:57.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "21.10.Dr",
      "21.60.Gx",
      "03.75.Hh",
      "21.10.Gv"
    ],
    "keywords": [
      "cluster structure",
      "hoyle-analogue state",
      "experimental energy levels",
      "orthogonality condition model",
      "gaussian expansion method"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review C",
      "year": 2010,
      "month": "Dec",
      "volume": 82,
      "number": 6,
      "pages": "064315"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 22,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 862385,
      "adsabs": "2010PhRvC..82f4315Y"
    }
  }
}