{
  "abstract": "We present FeynFacet, a workflow in which artificial intelligence agents develop and execute programs for analytic next-to-leading-order (NLO) QCD calculations, with the observables and conventions specified by physicists. We use it to derive new analytic hard functions for single-inclusive transverse spin transfer in proton-proton and lepton-proton collisions. The new proton-proton results cover all partonic channels contributing to transverse spin transfer, and the new lepton-proton result is inclusive in the scattered lepton. Within FeynFacet, we use reverse unitarity to represent the on-shell delta functions in real-emission phase-space integrals as cut propagators. Dimensional shifts convert integrals containing evanescent numerators into scalar integrals in higher dimensions. Integration-by-parts identities then reduce the scalar integrals to master integrals, which are evaluated analytically. Gauge invariance, pole cancellation and renormalization-group (RG) evolution provide checks throughout the calculation. We reproduce established single-inclusive hard functions for unpolarized and double longitudinally polarized proton-proton and lepton-proton scattering, and for proton-proton scattering with two transversely polarized beams. We also reproduce the NLO matching coefficients for unpolarized quark and gluon transverse-momentum-dependent parton distributions and the associated soft functions. The new transverse spin-transfer coefficients provide perturbative inputs for extracting quark transversity through spin-dependent fragmentation, including polarized-hyperon production, Collins and dihadron asymmetries in jets, and spin-dependent one- and two-point energy correlators. We make all analytic coefficients and the associated calculation programs publicly available online.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.31745",
  "author_total": 3,
  "authors": [
    {
      "name": "Zhong-Bo Kang"
    },
    {
      "name": "Werner Vogelsang"
    },
    {
      "name": "Congyue Zhang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/c00t8zp5jfx9j.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.31745",
  "fulltext_url": null,
  "id": "c00t8zp5jfx9j",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.31745",
  "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",
      "hep-th"
    ],
    [
      "openalex",
      "3106|Quantum Chromodynamics and Particle Interactions"
    ]
  ],
  "openalex": "W7223669505",
  "pdf_url": "https://arxiv.org/pdf/2610.31745",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-22",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/c00t8zp5jfx9j.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:15Z",
      "native_id": "2610.31745",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.31745"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ex",
      "subfield": "high-energy"
    }
  ],
  "title": "FeynFacet: AI agents for analytic NLO QCD",
  "title_text": "FeynFacet: AI agents for analytic NLO QCD",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:15Z",
  "url": "https://research.draconitic.com/paper/c00t8zp5jfx9j",
  "venue": "arXiv",
  "versions": []
}