{
  "abstract": "Three-dimensional femtoscopy probes the space-time structure of particle-emitting sources in relativistic heavy-ion collisions. The collision-energy dependence of Lévy source parameters may reveal the evolution of strongly interacting matter and possible signatures of the QCD phase diagram. We previously studied the excitation function of three-dimensional Lévy source parameters for pion pairs in Au+Au collisions with EPOS4, analyzing the pair-distance distribution \\(D(ρ)\\) through one-dimensional projections. Here, we analyze the full three-dimensional source distribution and correlation function directly. We construct \\(D(ρ_{\\rm out},ρ_{\\rm side},ρ_{\\rm long})\\) as a 3D histogram, transform it into \\(C(q_{\\rm out},q_{\\rm side},q_{\\rm long})\\) using a Fast Fourier Transform, and fit the correlation function with the analytic Lévy formula. This approach can reduce biases arising when one-dimensional projections are used to describe a non-elliptical source. We apply the method across the RHIC Beam Energy Scan range and compare the extracted energy dependence with results from the projection-based method and recent UrQMD calculations. We focus on the out-side observables \\(R_{\\rm diff}^{2}=R_{\\rm out}^{2}-R_{\\rm side}^{2}\\) and \\(R_{\\rm out}/R_{\\rm side}\\), whose different energy dependences in EPOS4 and UrQMD may illuminate the roles of emission duration and source dynamics. This work establishes a direct three-dimensional framework for comparison with future femtoscopic measurements and for exploring possible non-monotonic structures associated with the QCD phase diagram.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.18257",
  "author_total": 2,
  "authors": [
    {
      "name": "Yan Huang"
    },
    {
      "name": "Máté Csanád"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5besccdkvjwk6.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.18257",
  "fulltext_url": null,
  "id": "5besccdkvjwk6",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.18257",
  "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-ex"
    ],
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "arxiv",
      "nucl-th"
    ],
    [
      "openalex",
      "3106|High-Energy Particle Collisions Research"
    ]
  ],
  "openalex": "W7221817427",
  "pdf_url": "https://arxiv.org/pdf/2610.18257",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-13",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5besccdkvjwk6.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:11Z",
      "native_id": "2610.18257",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.18257"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ex",
      "subfield": "high-energy"
    },
    {
      "field": "physics",
      "origin": "arxiv:nucl-th",
      "subfield": "nuclear"
    }
  ],
  "title": "Femtoscopic parameters of pion emission sources in EPOS4 Au+Au collisions from 7.7 to 200 GeV",
  "title_text": "Femtoscopic parameters of pion emission sources in EPOS4 Au+Au collisions from 7.7 to 200 GeV",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:11Z",
  "url": "https://research.draconitic.com/paper/5besccdkvjwk6",
  "venue": "arXiv",
  "versions": []
}