{
  "abstract": "The production of $τ$ lepton pairs via photon-photon fusion, $γγ\\to ττ$, is studied in ultraperipheral lead-lead collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The dataset, collected by the CMS experiment in 2018, corresponds to an integrated luminosity of 1.70 nb$^{-1}$. Four different $τ^+τ^-$ decay final states are analyzed. A simultaneous likelihood fit to the measured lepton transverse momentum ($p_\\mathrm{T}$) distributions, which incorporates information from both spectral shape and normalization, is used to constrain the anomalous magnetic moment of the $τ$ lepton, $a_τ$, and to extract the cross section of the process. The measured 95% CL interval for $a_τ$ is $-$0.039 $\\lt$ $a_τ$ $\\lt$ 0.032. The fiducial cross section, $σ_{γγ\\to ττ}^\\text{fid}$ = 555$^{+60}_{-14}$ $μ$b for tau leptons with $p_\\mathrm{T}^τ$ $\\gt$ 1 GeV and pseudorapidity $\\lvertη^τ\\rvert$ $\\lt$ 3, is the most precise measurement for this process at the LHC to date and is in agreement with next-to-leading-order quantum electrodynamics predictions.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2607.20148",
  "author_total": 1,
  "authors": [
    {
      "name": "CMS Collaboration"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fy6cvf9cfh2qs.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2607.20148",
  "fulltext_url": null,
  "id": "fy6cvf9cfh2qs",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2607.20148",
  "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",
      "nucl-ex"
    ],
    [
      "openalex",
      "3106|Particle physics theoretical and experimental studies"
    ]
  ],
  "openalex": "W7170167703",
  "pdf_url": "https://arxiv.org/pdf/2607.20148",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/fy6cvf9cfh2qs.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:01Z",
      "native_id": "2607.20148",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2607.20148"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ex",
      "subfield": "high-energy"
    },
    {
      "field": "physics",
      "origin": "arxiv:nucl-ex",
      "subfield": "nuclear"
    }
  ],
  "title": "Measurement of the $γγ\\to ττ$ cross section and constraints on the anomalous magnetic moment of the $τ$ lepton in ultraperipheral PbPb collisions at $\\sqrt{s_\\mathrm{NN}}$ = 5.02 TeV",
  "title_text": "Measurement of the γγ→ ττ cross section and constraints on the anomalous magnetic moment of the τ lepton in ultraperipheral PbPb collisions at √(s_NN) = 5.02 TeV",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:01Z",
  "url": "https://research.draconitic.com/paper/fy6cvf9cfh2qs",
  "venue": "arXiv",
  "versions": []
}