{
  "abstract": "Belle II has reported a $2.7σ$ excess in $B^+\\to K^+ν\\barν$ over its Standard Model prediction, recently interpreted as arising from an axion-like particle mediating a thermal dark matter candidate. We reassess this interpretation using a new mass-differential measurement of the same data set and adding two visible-decay searches that earlier analyses omitted. The resulting bounds leave the predictions from a standard cosmological history only marginally compatible with the excess, viable in a narrow window of parameter space. Thus, we consider a situation where dark matter freezes out during a low-temperature reheating era, featuring entropy injection diluting the relic abundance. This requires smaller couplings compared to those in standard cosmology in order to match the observed dark matter density, opening a region of parameter space where the compatibility of the model with the Belle II excess is significantly improved.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.00460",
  "author_total": 3,
  "authors": [
    {
      "name": "Joel Jones-Pérez"
    },
    {
      "name": "Luca Merlo"
    },
    {
      "name": "Javier Silva-Malpartida"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2xgdet0kvak5d.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.00460",
  "fulltext_url": null,
  "id": "2xgdet0kvak5d",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.00460",
  "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",
      "hep-ph"
    ],
    [
      "openalex",
      "3106|Dark Matter and Cosmic Phenomena"
    ]
  ],
  "openalex": "W7215747255",
  "pdf_url": "https://arxiv.org/pdf/2610.00460",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/2xgdet0kvak5d.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:26:03Z",
      "native_id": "2610.00460",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.00460"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "ALP-Mediated Dark Matter at Low Reheating Temperature and the Belle II Excess",
  "title_text": "ALP-Mediated Dark Matter at Low Reheating Temperature and the Belle II Excess",
  "type": "preprint",
  "updated_at": "2026-10-30T12:26:03Z",
  "url": "https://research.draconitic.com/paper/2xgdet0kvak5d",
  "venue": "arXiv",
  "versions": []
}