{
  "annotation_id": "aac75bed-c64b-4a41-8573-dbc746a9aacd",
  "date_created": "2026-03-02T18:00:18.644000Z",
  "date_modified": "2026-03-02T18:00:18.644000Z",
  "file_hash": "408aacb4de8e8ad88d0508dc2489646bafb2b98057c46f4495f5cb801be5bff9",
  "private": false,
  "record": {
    "abstract": "We discuss two conditions needed for correct computation of $2\\nu \\beta\\beta$\nnuclear matrix-elements within the realistic shell-model framework. An\nalgorithm in which intermediate states are treated based on Whitehead\u0027s moment\nmethod is inspected, by taking examples of the double GT$^+$ transitions\n$\\mbox{$^{36}$Ar}\\rightarrow\\mbox{$^{36}$S}$,\n$\\mbox{$^{54}$Fe}\\rightarrow\\mbox{$^{54}$Cr}$ and $\\mbox{$^{58}$Ni}\n\\rightarrow\\mbox{$^{58}$Fe}$. This algorithm yields rapid convergence on the\n$2\\nu\\beta\\beta$ matrix-elements, even when neither relevant GT$^+$ nor GT$^-$\nstrength distribution is convergent. A significant role of the shell structure\nis pointed out, which makes the $2\\nu\\beta \\beta$ matrix-elements highly\ndominated by the low-lying intermediate states. Experimental information of the\nlow-lying GT$^\\pm$ strengths is strongly desired. Half-lives of\n$T^{2\\nu}_{1/2}({\\rm EC}/{\\rm EC};\n\\mbox{$^{36}$Ar}\\rightarrow\\mbox{$^{36}$S})=1.7\\times 10^{29}\\mbox{yr}$,\n$T^{2\\nu}_{1/2}({\\rm EC}/{\\rm EC};\\mbox{$^{54}$Fe}\\rightarrow\n\\mbox{$^{54}$Cr})=1.5\\times 10^{27}\\mbox{yr}$,$T^{2\\nu}_{1/2}({\\rm EC} /{\\rm\nEC};\\mbox{$^{58}$Ni}\\rightarrow\\mbox{$^{58}$Fe})=6.1\\times 10^{24}\\mbox{yr}$and\n$T^{2\\nu}_{1/2}(\\beta^+/{\\rm EC};\\mbox{$^{58}$Ni}\n\\rightarrow\\mbox{$^{58}$Fe})=8.6\\times 10^{25}\\mbox{yr}$ are obtained from the\npresent realistic shell-model calculation of the nuclear matrix-elements.",
    "arxiv_id": "nucl-th/9606023",
    "authors": [
      "H. Nakada",
      "T. Sebe",
      "K. Muto"
    ],
    "categories": [
      "nucl-th"
    ],
    "doi": "10.1016/0375-9474(96)00227-8",
    "journal_ref": "Nucl.Phys. A607 (1996) 235-249",
    "title": "Realistic shell model calculation of $2\\nu\\beta\\beta$ nuclear matrix   elements and role of shell structure in intermediate states",
    "url": "https://arxiv.org/abs/nucl-th/9606023"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "9611bbd0-7cfd-44b3-a2ca-8cdab52eb89a",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}