{
  "abstract": "The LUX-ZEPLIN experiment has reported a single nuclear recoil candidate at $E_R = 248 \\pm 23(\\mathrm{stat}) \\pm 23(\\mathrm{sys})$~keV, disfavouring the background-only hypothesis at a global significance of $2.6σ$. The difficulty such an event poses is not the recoil energy itself but the absence of any accompanying excess at low energy as elastic scattering of halo dark matter yields a monotonically falling spectrum, and supplying the required momentum transfer $q \\simeq 246$~MeV already demands $m_χ\\gtrsim 79$~GeV. We confront the event with the two kinematically distinct mechanisms that evade this limitation, endothermic inelastic dark matter, in which a mass splitting $δ\\sim \\mathcal{O}(100)$~keV forbids low-energy recoils and boosted dark matter, in which a light relativistic flux supplies the momentum, treating both with the same model-independent scalar--scalar, pseudoscalar--scalar and pseudoscalar--pseudoscalar effective operators. The two scenarios prove spectrally distinguishable. The inelastic spectra sit near the observed energy for every operator, placing only $6$--$17\\%$ of events below 150~keV, whereas the boosted spectra depend critically on the operator: the scalar and pseudoscalar--scalar interactions place $99\\%$ and $92\\%$ of their events below 150~keV, while the pseudoscalar--pseudoscalar interaction places $75\\%$ above it. Momentum dependence is thus essential to the boosted interpretation, but in the inelastic case it trades against the splitting, the preferred $δ$ decreasing monotonically from $\\mathcal{O}_{ss}$ to $\\mathcal{O}_{ps}$ to $\\mathcal{O}_{pp}$. Because the scenarios differ across the whole high-energy window, a handful of additional events would separate them, placing the question within reach of the full LZ exposure.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.14799",
  "author_total": 2,
  "authors": [
    {
      "name": "Satyabrata Mahapatra"
    },
    {
      "name": "Partha Kumar Paul"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/aqnjk5mvhqb7v.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.14799",
  "fulltext_url": null,
  "id": "aqnjk5mvhqb7v",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.14799",
  "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",
      "astro-ph.CO"
    ],
    [
      "arxiv",
      "hep-ex"
    ],
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "arxiv",
      "hep-th"
    ],
    [
      "openalex",
      "3106|Dark Matter and Cosmic Phenomena"
    ]
  ],
  "openalex": "W7213294209",
  "pdf_url": "https://arxiv.org/pdf/2609.14799",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-13",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/aqnjk5mvhqb7v.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:25Z",
      "native_id": "2609.14799",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.14799"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ex",
      "subfield": "high-energy"
    }
  ],
  "title": "Boosted or Inelastic? Discriminating Interpretations of the LZ 248 keV Event",
  "title_text": "Boosted or Inelastic? Discriminating Interpretations of the LZ 248 keV Event",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:25Z",
  "url": "https://research.draconitic.com/paper/aqnjk5mvhqb7v",
  "venue": "arXiv",
  "versions": []
}