{
  "annotation_id": "b4d25f8f-16c9-4a75-8f0e-841f0676f4ae",
  "date_created": "2026-03-02T18:00:22.147000Z",
  "date_modified": "2026-03-02T18:00:22.147000Z",
  "file_hash": "a4cb35d69ff2101b95def5df20f0714d0f125ed87a385cd0981604944ba66a60",
  "private": false,
  "record": {
    "abstract": "A new operator for pion photo- and electroproduction has been developed for\nnuclear applications at photon equivalent energies up to 1 GeV. The model\ncontains Born terms, vector mesons and nucleon resonances ($P_{33}(1232)$,\n$P_{11}(1440)$, $D_{13}(1520)$, $S_{11}(1535)$, $F_{15}(1680)$, and\n$D_{33}(1700)$). The resonance contributions are included taking into account\nunitarity to provide the correct phases of the pion photoproduction multipoles.\nThe $Q^2$ dependence of electromagnetic resonance vertices is described with\nappropriate form factors in the electromagnetic helicity amplitudes. Within\nthis model we have obtained good agreement with the experimental data for pion\nphoto- and electroproduction on the nucleon for both differential cross\nsections and polarization observables. The model can be used as a starting\npoint to predict and analyze forthcoming data.",
    "arxiv_id": "nucl-th/9807001",
    "authors": [
      "D. Drechsel",
      "O. Hanstein",
      "S. S. Kamalov",
      "L. Tiator"
    ],
    "categories": [
      "nucl-th"
    ],
    "doi": "10.1016/S0375-9474(98)00572-7",
    "journal_ref": "Nucl.Phys. A645 (1999) 145-174",
    "title": "A unitary isobar model for pion photo- and electroproduction on the   proton up to 1 GeV",
    "url": "https://arxiv.org/abs/nucl-th/9807001"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "993ffb52-ae18-42c1-9dfd-6747048a1755",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}