{
  "abstract": "Dark matter that is weakly mixed with particles in a thermal plasma can be produced through both, oscillatory and collisional freeze-in. While plasma effects have long been known to suppress the former, their role in collisional freeze-in remains less clear quantitatively, leading to conflicting results in sterile neutrino dark matter production via collisional freeze-in. Using first-principles nonequilibrium Kadanoff-Baym equations in the flavour-covariant formulation, we establish the general result that plasma effects also suppress collisional freeze-in: the vacuum mixing angle in the collision rate is replaced by its plasma-corrected counterpart. Applying this result, we conclude that sterile neutrinos cannot be dark matter in the keV-MeV mass range when produced from the Standard Model plasma.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.29911",
  "author_total": 2,
  "authors": [
    {
      "name": "Shao-Ping Li"
    },
    {
      "name": "Josef Pradler"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3b7br22e9nhv6.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.29911",
  "fulltext_url": null,
  "id": "3b7br22e9nhv6",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.29911",
  "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-ph"
    ],
    [
      "openalex",
      "3106|Dark Matter and Cosmic Phenomena"
    ]
  ],
  "openalex": "W7214396205",
  "pdf_url": "https://arxiv.org/pdf/2609.29911",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-24",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3b7br22e9nhv6.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:24:11Z",
      "native_id": "2609.29911",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.29911"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Plasma Effects Suppress Mixing-Induced Collisional Freeze-In",
  "title_text": "Plasma Effects Suppress Mixing-Induced Collisional Freeze-In",
  "type": "preprint",
  "updated_at": "2026-10-30T12:24:11Z",
  "url": "https://research.draconitic.com/paper/3b7br22e9nhv6",
  "venue": "arXiv",
  "versions": []
}