{
  "abstract": "We study a dark photon dark matter scenario associated with a gauged $U(1)_X$ symmetry, stabilized by a dark parity that forbids kinetic mixing with the Standard Model. The leading interactions between the dark photon dark matter and the Standard Model arise from dimension-six Higgs-portal operators. In previous work, we found that for the parity-violating operator, the dark matter annihilation process is $p$-wave suppressed, naturally evading stringent direct-detection constraints while reproducing the observed relic abundance through thermal freeze-out. For a cutoff scale of 1 TeV, a dark matter mass of around 400 GeV is favored to realize the observed relic abundance. This scenario predicts cosmic-ray signals, in particular in the $W^{+}W^{-}$ channel, which can be targeted by indirect-detection experiments. Recently, a halo-like gamma-ray excess has been reported by Totani. Assuming a Navarro-Frenk-White-$ρ^2$ morphology for the dark matter distribution,a dark matter mass of 420 GeV is favored for the $W^{+}W^{-}$ final state. Motivated by this excess, we consider the present dark photon dark matter framework augmented by a CP-even sub-GeV scalar mediator, which couples to the dark photon mass operator in order to enhance the present-day annihilation rate in the Galactic halo while inducing only an O(1) correction at freeze-out. The exchange of this scalar induces a long-range attractive force, leading to Sommerfeld enhancement of the annihilation rate. The enhancement is saturating in dwarf spheroidal galaxies and the annihilation rate is dropping as $p$-wave remaining consistent with constraints from dwarf galaxies and cosmology.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Nucl. Phys. B 1031 (2026) 117671",
  "arxiv": "2605.09979",
  "author_total": 1,
  "authors": [
    {
      "name": "Kimiko Yamashita"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/amy1hcvq5zq8n.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2605.09979",
  "fulltext_url": null,
  "id": "amy1hcvq5zq8n",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2605.09979",
  "language": null,
  "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",
      "hep-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2605.09979",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-26",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/amy1hcvq5zq8n.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:12Z",
      "native_id": "2605.09979",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2605.09979"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Higgs-Portal Spin-1 Dark Matter with Parity-Violating Interaction for a Galactic Halo Gamma Ray Excess",
  "title_text": "Higgs-Portal Spin-1 Dark Matter with Parity-Violating Interaction for a Galactic Halo Gamma Ray Excess",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:12Z",
  "url": "https://research.draconitic.com/paper/amy1hcvq5zq8n",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1016/j.nuclphysb.2026.117671",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}