{
  "abstract": "Late-time cosmic acceleration is conventionally ascribed to a cosmological constant, though $Λ$CDM continues to face several theoretical difficulties that keep alternative gravity models under active consideration. This work examines the Hu-Sawicki $f(R)$ model in a spatially non-flat background, with the modified-gravity parameter $b$ and the curvature density $Ω_k$ both treated as free parameters, constrained using DESI-DR2 BAO, BBN, and four Type Ia supernova compilations -- PantheonPlus, PantheonPlus+SH0ES, Union3, and DESY5yr. Across all four combinations, $H_0$ and $Ω_m$ stay close to their $Λ$CDM values, with a noticeable shift in $H_0$ appearing only for the SH0ES-calibrated dataset. The parameter $b$ departs from zero at better than $2σ$ in three of the four fits, most prominently for DESY5yr, whereas the SH0ES-calibrated combination alone prefers $b<0$. A strong positive correlation among $b$, $H_0$, and $Ω_k$ underlies this shift, suggesting that curvature signatures obtained under $Λ$CDM can be reabsorbed into the modified-gravity sector once this additional freedom is allowed. Statistical model comparison via AIC and BIC gives a mixed picture: AIC leans toward the Hu-Sawicki model in three of the four combinations, while BIC's heavier penalty on the extra parameter favors $Λ$CDM in most cases, and only DESY5yr is preferred under both criteria. These findings show that the Hu-Sawicki $f(R)$ scenario with unconstrained curvature is nonetheless a statistically feasible, if not obviously preferred, alternative to $Λ$CDM, and that curvature restrictions generated inside $Λ$CDM cannot be viewed as independent of the underlying gravity model.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.17643",
  "author_total": 5,
  "authors": [
    {
      "name": "Saurabh Verma"
    },
    {
      "name": "Manish Yadav"
    },
    {
      "name": "Archana Dixit"
    },
    {
      "name": "Anirudh Pradhan"
    },
    {
      "name": "M. S. Barak"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/7364k5mjd75zw.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.17643",
  "fulltext_url": null,
  "id": "7364k5mjd75zw",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.17643",
  "language": null,
  "licence": "CC0-1.0",
  "licence_label": "CC0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/publicdomain/zero/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "gr-qc"
    ],
    [
      "openalex",
      "3103|Cosmology and Gravitation Theories"
    ]
  ],
  "openalex": "W7213497540",
  "pdf_url": "https://arxiv.org/pdf/2609.17643",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-15",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/7364k5mjd75zw.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:22:01Z",
      "native_id": "2609.17643",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.17643"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    }
  ],
  "title": "Hu-Sawicki $f(R)$ Gravity in a Non-Flat Universe: Constraints from DESI-DR2, BBN, and Type Ia Supernovae",
  "title_text": "Hu-Sawicki f(R) Gravity in a Non-Flat Universe: Constraints from DESI-DR2, BBN, and Type Ia Supernovae",
  "type": "preprint",
  "updated_at": "2026-10-30T12:22:01Z",
  "url": "https://research.draconitic.com/paper/7364k5mjd75zw",
  "venue": "arXiv",
  "versions": []
}