{
  "abstract": "We propose a unified $A_4\\times Z_2\\times U(1)_L$ framework for generating small Dirac neutrino masses and address dark matter through feeble interactions in an extended particle physics model. The model extends the Standard Model with a pair of heavy vector-like neutral $A_4$ fermions $N(N_{L,R})$, two additional flavon fields $η$ and $ϕ$, among which $η$ being a $Z_2$-odd inert scalar and a dark-sector vector-like fermion field $χ$. We numerically explore the Dirac-sector Yukawa couplings and identify the parameter region that is consistent with the {\\tt NuFit 6.1} neutrino oscillation data at the $3σ$ level. The dark matter candidate $χ$, stabilized by the $Z_2$ symmetry, is produced non-thermally through the decay $N_L\\rightarrowχ+η$. By solving the Boltzmann equation, we find that the observed relic abundance, $Ω_{\\rm DM}h^2\\simeq0.12$, can be reproduced for freeze-in couplings of order $λ\\sim10^{-5.5}$--$10^{-7.5}$ over the considered dark matter mass range. For the chosen parameter space, we also verify the interaction rate remains below the Hubble expansion rate, confirming $χ$ never reaches thermal equilibrium. Thus, our results demonstrate that the model provides a consistent realization of Dirac neutrino masses and FIMP dark matter within a common symmetry-based setup. The presence of light Dirac RH neutrinos can contribute to the dark radiation and hence the effective degrees of freedom via thermal and non-thermal processes. We further estimate the contribution of the light right-handed neutrinos to \\(ΔN_{\\rm eff}\\), finding a maximum characteristic value of \\(ΔN_{\\rm eff}\\simeq0.14\\) in the benchmark parameter region.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.15618",
  "author_total": 3,
  "authors": [
    {
      "name": "Pritam Das"
    },
    {
      "name": "Anupam Deka"
    },
    {
      "name": "Debajyoti Dutta"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/83rwz6fg1cpdv.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.15618",
  "fulltext_url": null,
  "id": "83rwz6fg1cpdv",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.15618",
  "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",
      "hep-ph"
    ],
    [
      "openalex",
      "3106|Particle physics theoretical and experimental studies"
    ]
  ],
  "openalex": "W7221759294",
  "pdf_url": "https://arxiv.org/pdf/2610.15618",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-11",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/83rwz6fg1cpdv.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:06Z",
      "native_id": "2610.15618",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.15618"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "From Dirac Neutrino Mass to Dark Radiation: An $A_4$-Symmetric FIMP Dark Matter Framework",
  "title_text": "From Dirac Neutrino Mass to Dark Radiation: An A_4-Symmetric FIMP Dark Matter Framework",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:06Z",
  "url": "https://research.draconitic.com/paper/83rwz6fg1cpdv",
  "venue": "arXiv",
  "versions": []
}