{
  "abstract": "Low-energy positron scattering from singlet and triplet metastable He($1s2s$) is investigated using the $R$-matrix propagation method in hyperspherical coordinates. Elastic and positronium-formation cross sections are reported, and near-threshold resonance structures are analyzed in terms of eigenphase sums and the time-delay matrix. For the triplet target, the calculated cross sections are in agreement with available convergent-close-coupling results and display the expected threshold behavior. Beyond the known $S$-wave features, Feshbach resonance series in higher partial waves extending up to highly excited atomic thresholds are systematically identified. The time-delay matrix further uncovers hidden resonances that produce obvious structures in the positronium-formation cross sections.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2606.29253",
  "author_total": 4,
  "authors": [
    {
      "name": "Ning-Ning Gao"
    },
    {
      "name": "Hui-Li Han"
    },
    {
      "name": "Ting-Yun Shi"
    },
    {
      "name": "Li-Yan Tang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5kfn13zr0mbne.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.29253",
  "fulltext_url": null,
  "id": "5kfn13zr0mbne",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.29253",
  "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",
      "physics.atom-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2606.29253",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-18",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5kfn13zr0mbne.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:03Z",
      "native_id": "2606.29253",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.29253"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.atom-ph",
      "subfield": "amo"
    }
  ],
  "title": "Low-energy positron scattering from metastable helium",
  "title_text": "Low-energy positron scattering from metastable helium",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:03Z",
  "url": "https://research.draconitic.com/paper/5kfn13zr0mbne",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1103/6m7n-md66",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}