{
  "abstract": "We investigate the level shifts in protonium using the framework of non-relativistic effective field theory (NREFT). Our study is prompted by the PUMA collaboration's plans to probe the neutron-to-proton ratio in the nuclear density tail using antiprotonic atoms -- a method for which light atoms provide an important benchmark. We calculate the corrections to the Deser-Goldberger-Baumann-Thirring formula for the complex level shift of S-wave states from the unitary cusp and Coulomb photon exchange. Structure dependent corrections enter at the next order. For higher-partial-wave states, they enter already at leading order. Using input from chiral NNbar interactions, we compare to other calculations and measurements from LEAR.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.06624",
  "author_total": 2,
  "authors": [
    {
      "name": "Hans-Werner Hammer"
    },
    {
      "name": "Akaki Rusetsky"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ebpwh0h5jtb2c.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.06624",
  "fulltext_url": null,
  "id": "ebpwh0h5jtb2c",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.06624",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "arxiv",
      "nucl-th"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2609.06624",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-06",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/ebpwh0h5jtb2c.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:48Z",
      "native_id": "2609.06624",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.06624"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    },
    {
      "field": "physics",
      "origin": "arxiv:nucl-th",
      "subfield": "nuclear"
    }
  ],
  "title": "Effective Field Theory of Protonium",
  "title_text": "Effective Field Theory of Protonium",
  "type": "preprint",
  "updated_at": "2026-10-30T12:19:48Z",
  "url": "https://research.draconitic.com/paper/ebpwh0h5jtb2c",
  "venue": "arXiv",
  "versions": []
}