{
  "abstract": "We present a phenomenological study of the longitudinal unpolarized structure function $F_{UU,L}$ in semi-inclusive deep inelastic scattering (SIDIS) and its ratio with the transverse structure function, $R_{\\, \\rm SIDIS}=F_{UU,L}/F_{UU,T}$. We study their transverse-momentum dependence, combining for the first time low- and high-transverse-momentum contributions across the kinematic range relevant to SIDIS measurements. At low transverse momentum, $F_{UU,L}$ is power suppressed, making it sensitive to next-to-next-to-leading-power dynamics in the unpolarized sector. We find that this contribution can be sizable, with $R_{\\, \\rm SIDIS}\\simeq 0.3$ at low transverse momentum and hard scale, producing a correction of the order of $10\\%$ to transverse-momentum-integrated observables. Although these estimates remain subject to theoretical uncertainties, our results indicate that accounting for $F_{UU,L}$ is likely to be important for the interpretation of SIDIS multiplicities and motivate dedicated measurements of $R_{\\, \\rm SIDIS}$ to better constrain the longitudinal contribution.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.06628",
  "author_total": 4,
  "authors": [
    {
      "name": "Alessandro Bacchetta"
    },
    {
      "name": "Matteo Cerutti"
    },
    {
      "name": "Leonard Gamberg"
    },
    {
      "name": "Richard Whitehill"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/0e239wgjk8rfv.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.06628",
  "fulltext_url": null,
  "id": "0e239wgjk8rfv",
  "issns": [],
  "landing_url": "https://hal.science/hal-05835137v1",
  "language": "en",
  "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"
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      "hal",
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      "openalex",
      "3106|Quantum Chromodynamics and Particle Interactions"
    ]
  ],
  "openalex": "W7220719766",
  "pdf_url": "https://arxiv.org/pdf/2610.06628",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/0e239wgjk8rfv.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:00Z",
      "native_id": "hal-05835137",
      "source": "hal",
      "url": "https://hal.science/hal-05835137v1"
    },
    {
      "first_seen": "2026-10-30T12:27:01Z",
      "native_id": "2610.06628",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.06628"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ex",
      "subfield": "high-energy"
    }
  ],
  "title": "Phenomenological Estimate for the Longitudinal Unpolarized Structure Function in Semi-inclusive Deep Inelastic Scattering",
  "title_text": "Phenomenological Estimate for the Longitudinal Unpolarized Structure Function in Semi-inclusive Deep Inelastic Scattering",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:01Z",
  "url": "https://research.draconitic.com/paper/0e239wgjk8rfv",
  "venue": "HAL",
  "versions": []
}