{
  "abstract": "We show that a dark-photon dark matter framework can simultaneously account for two recently reported anomalies: the halo-like Galactic gamma-ray excess identified by Totani in 15 years of Fermi-LAT data, and the $E_{\\rm nr}=248\\pm23\\,({\\rm stat})\\pm23\\,({\\rm sys})$ keV nuclear-recoil event of interest reported by the LUX-ZEPLIN Collaboration. The dark matter is a $U(1)_X$ dark photon $X$ with mass $m_X=420$ GeV, stabilized by a dark parity that forbids kinetic mixing with the Standard Model photon. A light scalar mediator $ϕ$, required to explain the Totani excess via Sommerfeld enhancement, is joined by a second light scalar $ϕ'$ that couples a nearly degenerate heavier vector partner $V$ to $X$. The resulting inelastic transition $X+N\\to V+N$, with mass splitting $δ\\simeq316$ keV close to the kinematic endpoint for $m_X=420$ GeV, naturally reproduces the localized LZ event once the detector energy resolution is included, while leaving the relic abundance and the halo phenomenology of the original Totani-motivated benchmark essentially unchanged.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Physics , Ibaraki University , Mito 310-8512 , Japan"
  ],
  "article_type": null,
  "arxiv": "2609.02868",
  "author_total": 1,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Kimiko Yamashita",
      "orcid": "0000-0002-5033-5234"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4mh9rbf4jfm73.bib",
  "cited_by": 67,
  "doi": "10.48550/arxiv.2609.02868",
  "fulltext_url": null,
  "id": "4mh9rbf4jfm73",
  "issns": [
    "2331-8422"
  ],
  "landing_url": "https://arxiv.org/abs/2609.02868",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.HE"
    ],
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      "arxiv",
      "hep-ph"
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    [
      "openalex",
      "3106|Dark Matter and Cosmic Phenomena"
    ]
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  "openalex": "W7207614664",
  "pdf_url": "https://arxiv.org/pdf/2609.02868",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-02",
  "publisher": "Cornell University",
  "ris": "https://research.draconitic.com/paper/4mh9rbf4jfm73.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:31Z",
      "native_id": "2609.02868",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.02868"
    },
    {
      "first_seen": "2026-11-07T13:20:44Z",
      "native_id": "W7207614664",
      "source": "openalex",
      "url": "https://arxiv.org/abs/2609.02868"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Inelastic Dark Photon Dark Matter for the LUX-ZEPLIN High-Recoil Event and the Galactic Halo Gamma-Ray Excess",
  "title_text": "Inelastic Dark Photon Dark Matter for the LUX-ZEPLIN High-Recoil Event and the Galactic Halo Gamma-Ray Excess",
  "type": "preprint",
  "updated_at": "2026-11-08T13:20:37Z",
  "url": "https://research.draconitic.com/paper/4mh9rbf4jfm73",
  "venue": "arXiv",
  "versions": []
}