{
  "abstract": "We show that a minimal extension of the Standard Model (SM) by a single complex scalar $ϕ$ provides a viable inelastic exothermic, thermal relic, interpretation of the recently reported nuclear-recoil candidate from LUX-ZEPLIN (LZ). The mass terms and Higgs-portal interactions split $ϕ$ into two nearly degenerate real scalars, $ϕ_{1,2}$. For mass-splitting of a few hundred keV, $ϕ_2$ is cosmologically long-lived and the two states have comparable relic abundances. Taking $ϕ_{1,2}$ masses to be $\\sim100\\,$GeV, with off-diagonal Higgs coupling fixed by relic abundance, the exothermic down-scattering yields an order-one event expectation for the LZ exposure, without relying on the high-velocity tail of the dark matter velocity distribution required in endothermic scenarios. This scenario can be tested using different nuclear targets and with indirect dark matter searches: $ϕ_2\\toϕ_1γγ$ decays give a broad sub-MeV photon continuum that can be probed by INTEGRAL/SPI and COSI; $ϕ_1ϕ_2$ annihilation produces a GeV-scale continuum, extending up to $\\sim$100 GeV, that is probed by Fermi-LAT observations of dwarf galaxies; current CMB constraints are satisfied and annihilation among dark matter particles captured in the Sun is strongly suppressed. Next-generation experiments could probe correlated scattering, decay, and annihilation signatures of this thermal Higgs-portal scenario.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.01158",
  "author_total": 2,
  "authors": [
    {
      "name": "Subhojit Roy"
    },
    {
      "name": "Jure Zupan"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/38npngsp61ezj.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.01158",
  "fulltext_url": null,
  "id": "38npngsp61ezj",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.01158",
  "language": null,
  "licence": "CC0-1.0",
  "licence_label": "CC0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/publicdomain/zero/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.CO"
    ],
    [
      "arxiv",
      "astro-ph.HE"
    ],
    [
      "arxiv",
      "hep-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.01158",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/38npngsp61ezj.ris",
  "sources": [
    {
      "first_seen": "2026-11-03T12:20:59Z",
      "native_id": "2611.01158",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.01158"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Exothermic Higgs portal: from LUX-ZEPLIN recoil to Gamma Rays",
  "title_text": "Exothermic Higgs portal: from LUX-ZEPLIN recoil to Gamma Rays",
  "type": "preprint",
  "updated_at": "2026-11-05T15:20:18Z",
  "url": "https://research.draconitic.com/paper/38npngsp61ezj",
  "venue": "arXiv",
  "versions": []
}