{
  "annotation_id": "bdec0bfb-5007-4e90-b904-97b7e2425d6b",
  "date_created": "2026-03-02T18:00:04.921000Z",
  "date_modified": "2026-03-02T18:00:04.921000Z",
  "file_hash": "a882258e95c505c235e2bc9024d4d0d1f64f4a68abb736cdc5ca8dfd021e6c22",
  "private": false,
  "record": {
    "abstract": "We present a pion photoproduction model on the free nucleon based on an\nEffective Lagrangian Approach (ELA) which includes the nucleon resonances\n($\\Delta(1232)$, N(1440), N(1520), N(1535), $\\Delta (1620)$, N(1650), and\n$\\Delta (1700)$), in addition to Born and vector meson exchange terms. The\nmodel incorporates a new theoretical treatment of spin-3/2 resonances, first\nintroduced by Pascalutsa, avoiding pathologies present in previous models.\nOther main features of the model are chiral symmetry, gauge invariance, and\ncrossing symmetry. We use the model combined with modern optimization\ntechniques to assess the parameters of the nucleon resonances on the basis of\nworld data on electromagnetic multipoles. We present results for\nelectromagnetic multipoles, differential cross sections, asymmetries, and total\ncross sections for all one pion photoproduction processes on free nucleons. We\nfind overall agreement with data from threshold up to 1 GeV in laboratory\nframe.",
    "arxiv_id": "nucl-th/0509020",
    "authors": [
      "C. Fernandez-Ramirez",
      "E. Moya de Guerra",
      "J. M. Udias"
    ],
    "categories": [
      "nucl-th"
    ],
    "doi": "10.1016/j.aop.2006.02.009",
    "journal_ref": "Annals Phys. 321 (2006) 1408-1456",
    "title": "Effective Lagrangian Approach to pion photoproduction from the nucleon",
    "url": "https://arxiv.org/abs/nucl-th/0509020"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "762bba97-d9bb-4092-84af-f43ae4590713",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}