{
  "abstract": "We analyse the process $e^+e^-\\to hγ$ in the Standard Model (SM) and in generic extensions with heavy new physics, using the framework of Higgs pseudo-observables. We decompose the one-loop amplitude into separately gauge-invariant photon-pole, $Z$-pole, and non-pole contributions. For heavy new physics, we show that the leading deviations from the SM are necessarily encoded in the $hγγ$ and $hZγ$ on-shell effective couplings. Genuine $e^+e^-hγ$ contact interactions arise only at higher orders in a derivative expansion, both in SMEFT and HEFT. Although Higgs decays constrain the magnitudes of these pseudo-observables, they leave their relative sign undetermined. Measurements of $e^+e^-\\to hγ$ at different FCC-ee energies can resolve this ambiguity. Deviations incompatible with this description would instead point towards relatively light new degrees of freedom, as illustrated by a simplified $Z'$ model.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.35981",
  "author_total": 4,
  "authors": [
    {
      "name": "Fausto Boniotti"
    },
    {
      "name": "Gino Isidori"
    },
    {
      "name": "Christiane Mayer"
    },
    {
      "name": "Emanuelle Pinsard"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2mnnp5zv35hpq.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.35981",
  "fulltext_url": null,
  "id": "2mnnp5zv35hpq",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.35981",
  "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-ph"
    ],
    [
      "openalex",
      "3106|Particle physics theoretical and experimental studies"
    ]
  ],
  "openalex": "W7214962019",
  "pdf_url": "https://arxiv.org/pdf/2609.35981",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-28",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/2mnnp5zv35hpq.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:31Z",
      "native_id": "2609.35981",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.35981"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Higgs pseudo-observables in $e^+e^-\\to hγ$",
  "title_text": "Higgs pseudo-observables in e^+e^-→ hγ",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:31Z",
  "url": "https://research.draconitic.com/paper/2mnnp5zv35hpq",
  "venue": "arXiv",
  "versions": []
}