{
  "abstract": "In this work we calculate, for the first time, the dominant perturbative contributions to axion--matter couplings explicitly in string theory. Concretely, we compute these couplings in Calabi--Yau compactifications of heterotic string theory where the vector bundle is a sum of line bundles. They are expressed as overlap integrals requiring the Ricci-flat metric, the Hermitian Yang-Mills bundle metric, and the matter field harmonic forms. We compute these by solving the corresponding coupled differential equations with neural networks. Our results establish a characteristic hierarchy of four-dimensional couplings: axions couple to fermions as $\\mathcal{L} \\supset c_ψ\\,\\frac{\\partial_μa}{f_a}\\, ψ^\\dagger \\barσ^μψ$ with $c_ψ$ an $\\mathcal{O}(1)$ function of Kähler moduli for the model-dependent axions, while the corresponding coupling for the model-independent axion is suppressed by $α_{\\rm YM}$ at the ultraviolet matching scale. The model-dependent axions thus couple to fermions similarly as DFSZ-like four-dimensional axions, whereas the model-independent axion's couplings are loop-suppressed as in KSVZ-like constructions. The methods developed here apply directly to the large class of heterotic line bundle models with realistic spectra, and can be adapted to type II constructions.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.20911",
  "author_total": 4,
  "authors": [
    {
      "name": "Joshua N. Benabou"
    },
    {
      "name": "Naomi Gendler"
    },
    {
      "name": "Thomas R. Harvey"
    },
    {
      "name": "Jakob Moritz"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/77ry9rk96wryr.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.20911",
  "fulltext_url": null,
  "id": "77ry9rk96wryr",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.20911",
  "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"
    ],
    [
      "arxiv",
      "hep-th"
    ],
    [
      "openalex",
      "3106|Black Holes and Theoretical Physics"
    ]
  ],
  "openalex": "W7213880227",
  "pdf_url": "https://arxiv.org/pdf/2609.20911",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/77ry9rk96wryr.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:22Z",
      "native_id": "2609.20911",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.20911"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Calculating Axion-Matter Couplings in String Theory",
  "title_text": "Calculating Axion-Matter Couplings in String Theory",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:22Z",
  "url": "https://research.draconitic.com/paper/77ry9rk96wryr",
  "venue": "arXiv",
  "versions": []
}