{
  "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 N N ¯ interactions, we compare to other calculations and measurements from LEAR.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "name": "Hans-Werner Hammer",
      "orcid": "0000-0002-2318-0644"
    },
    {
      "name": "Akaki Rusetsky",
      "orcid": "0000-0002-4288-8672"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9ed3r96g0qcmt.bib",
  "cited_by": 0,
  "doi": "10.1016/j.physletb.2026.141071",
  "fulltext_url": "http://www.sciencedirect.com/science/article/pii/S0370269326009214",
  "id": "9ed3r96g0qcmt",
  "issns": [
    "0370-2693",
    "1873-2445"
  ],
  "landing_url": "https://linkinghub.elsevier.com/retrieve/pii/S0370269326009214",
  "language": "en",
  "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": null,
  "native_subjects": [
    [
      "lcc",
      "QC1-999"
    ],
    [
      "openalex",
      "3106|Quantum Chromodynamics and Particle Interactions"
    ]
  ],
  "openalex": "W7212055915",
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-30",
  "publisher": "Elsevier BV",
  "ris": "https://research.draconitic.com/paper/9ed3r96g0qcmt.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:06Z",
      "native_id": "10.1016/j.physletb.2026.141071",
      "source": "crossref",
      "url": "https://linkinghub.elsevier.com/retrieve/pii/S0370269326009214"
    },
    {
      "first_seen": "2026-10-30T13:47:21Z",
      "native_id": "88a5c1382bc74ff8be83e341d642cc7b",
      "source": "doaj",
      "url": "https://doi.org/10.1016/j.physletb.2026.141071"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "openalex:3106|Quantum Chromodynamics and Particle Interactions",
      "subfield": "high-energy"
    }
  ],
  "title": "Effective field theory of protonium",
  "title_text": "Effective field theory of protonium",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T13:47:21Z",
  "url": "https://research.draconitic.com/paper/9ed3r96g0qcmt",
  "venue": "Physics Letters B",
  "versions": []
}