{
  "abstract": "We investigate cosmological constraints on extra radiation and axionlike early dark energy (EDE), allowing primordial lepton asymmetry or light-quark-mass variation during big bang nucleosynthesis (BBN). We combine Planck CMB, DESI DR2 BAO, Pantheon+ supernovae, and primordial helium and deuterium measurements. When both extra radiation and lepton asymmetry are allowed, we obtain $N_{\\rm eff}=3.27\\pm0.16$, $ξ=0.017\\pm0.011$, and $H_0=69.24\\pm0.92\\,{\\rm km\\,s^{-1}\\,Mpc^{-1}}$. A positive lepton asymmetry compensates the helium increase caused by extra radiation, allowing a higher inferred Hubble constant even with the LBT helium measurement, which agrees with standard BBN. For EDE, primordial-abundance measurements instead restrict the higher baryon densities associated with larger EDE fractions, which reduce the predicted deuterium abundance. Allowing lepton asymmetry does not relax this restriction. In contrast, a positive light-quark-mass variation increases deuterium and compensates this reduction, permitting larger EDE fractions and a higher inferred Hubble constant. The same variation leaves the extra-radiation constraint nearly unchanged. We also find that allowing lepton asymmetry relaxes the 95\\% upper limit on the summed neutrino mass from $0.0640\\,{\\rm eV}$ to $0.0777\\,{\\rm eV}$ in the extra-radiation model.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.39579",
  "author_total": 1,
  "authors": [
    {
      "name": "Yo Toda"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5fqsrgx56df4r.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.39579",
  "fulltext_url": null,
  "id": "5fqsrgx56df4r",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.39579",
  "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": null,
  "pdf_url": "https://arxiv.org/pdf/2610.39579",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-29",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5fqsrgx56df4r.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:36:23Z",
      "native_id": "2610.39579",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.39579"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Cosmological constraints on extra radiation and early dark energy with lepton asymmetry and varying quark masses",
  "title_text": "Cosmological constraints on extra radiation and early dark energy with lepton asymmetry and varying quark masses",
  "type": "preprint",
  "updated_at": "2026-11-01T12:20:45Z",
  "url": "https://research.draconitic.com/paper/5fqsrgx56df4r",
  "venue": "arXiv",
  "versions": []
}