{
  "abstract": "A possible gamma-ray excess from the Galactic halo favors dark matter with a mass of several hundred GeV. In previous work, we found that an electroweak scalar doublet is a particularly economical, and nearly uniquely selected, interpretation among simple renormalizable thermal dark-matter models. We point out that its unbroken Z_2 symmetry is exactly equivalent to an interchange symmetry between two Higgs doublets, making dark matter the Z_2-odd partner of the Standard Model Higgs boson and suggesting that the two doublets may share a common weak-scale origin. We connect this model to the recently reported 248 keV nuclear-recoil event in the LUX-ZEPLIN experiment. For dark-matter masses of 440--600 GeV, a technically natural, mass-dependent neutral-state splitting of order 350 keV defines a narrow strip near the kinematic boundary where the fixed off-diagonal Z interaction can produce the observed recoil. Because the scattering probes the extreme high-velocity tail of the Galactic distribution, this interpretation predicts a large annual modulation, with future events preferentially occurring around early summer. Neither observation is yet conclusive, but their common interpretation is sharply testable.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.02505",
  "author_total": 1,
  "authors": [
    {
      "name": "Yasunori Nomura"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/afcyfx5xxaha2.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.02505",
  "fulltext_url": null,
  "id": "afcyfx5xxaha2",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.02505",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.CO"
    ],
    [
      "arxiv",
      "hep-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2609.02505",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/afcyfx5xxaha2.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:20:12Z",
      "native_id": "2609.02505",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.02505"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Dark Matter as the Z_2 Partner of the Standard Model Higgs Boson",
  "title_text": "Dark Matter as the Z_2 Partner of the Standard Model Higgs Boson",
  "type": "preprint",
  "updated_at": "2026-10-30T12:20:12Z",
  "url": "https://research.draconitic.com/paper/afcyfx5xxaha2",
  "venue": "arXiv",
  "versions": []
}